Alex and Olivier Armstrong. Alex Armstrong, a.k.a. Colonel Clean, is the almost grotesquely overmuscled poster boy for Pec Flex and prone to fits of staggering overacting at every possible opportunity, often with Manly Tears, and he's actually a total softy. His older sister Olivier is a Badass Normal of epic proportions, a slim, Magnificent BitchSocial DarwinistLady of War who can call Ed short without him even trying to argue and has no compunction about killing representatives from Central because they tried to get her involved in a soul-stealing murder conspiracy that amounts to betraying the whole country, and tried to take her men away, and pushing their bodies into wet concrete.
The 2003 anime version and light novels also have Fletcher and Russel Tringham, who present many parallels with the Elric brothers. So much so that not only do they impersonate the Elrics at least twice, there's a certain amount of Sibling Yin Yang between respective imposters-the Tringhams fulfill a certain amount of the expectation of what you're going to get with the Elrics, which is quite different from what you actually get. Aside from the fact that each Tringham has an ego that matches his respective Elric.
Light and his sister in Death Note. Their only common points are that they are both good-looking and respected. She is a nice, ordinary person, he is a freakishly intelligent Well-Intentioned Extremist with sociopathic tendencies and a god complex.
Twin examples: Risa and Riku in D.N.Angel; Vash and Knives in Trigun; Abel and Cain in Trinity Blood; Metatron and Sandalphon in Angel Sanctuary; Chrno and Aion/Ion in Chrono Crusade; Suboshi and Amiboshi in Fushigi Yuugi. Also as is often the case for the twin archetype, which some scholars view as a sub-category of the hermaphrodite archetype (seriously), one twin is gendered more 'feminine' (Risa, Vash, Abel, Chrno, arguably Metatron) and the other more 'masculine' (Riku, Knives, Cain, Aion, Sandalphon). (This has nothing to do with sexual orientation!)
This trope is even lampshaded by the twins in D.N.Angel:
Riku: We have absolutely nothing in common!
Risa: Nothing at all!
Soma and Kanna from Devil & Devil, Soma is a weak ocult otaku and kanna is a violent rebel, it doesn't help that they each get possessed by the devil Sword and the angel Ios respectably.
Yoh and Minatsuki in Deadman Wonderland are an interesting case: both are liars, cowards, and opportunists, but Yoh may be fundamentally a caring guy while his sister is a Yandere.
Jun Ushiro and his sister Kana in Bokurano. She is sweet, shy and forgiving, he is violent and brooding.
Anna and Johan in Monster. Anna is outgoing, compassionate, helpful and an idealistic humanist. Johan is quiet, introspective, manipulative and an utter sociopath. And he's the titular character.
In Hajime No Ippo, there's Kumi Mashiba, Ippo's main love-interest and then there's her big brother, Ryo 'The Executioner' Mashiba, an angry and brooding boxer who eagerly uses intimidation-tactics and fouls to beat down his opponents, and just generally comes across as a borderline psychopath. About the only person who's NOT scared of him is Kumi, who have been known to slap him to the floor when he got out of hand. There's also the fact that Mashiba practically raised Kumi ever since they were orphaned in an accident, so only she and one of his bosses know how hard Mashiba has worked to take care of her. The scene where this softer side of his' was shown was quite the Tear Jerker in the anime.
The Chizeta princesses from Magic Knight Rayearth: Tarta the younger is loud, rude, and Hot-Blooded while Tatra the elder is quiet, polite, and a total pushover (apparently), which is probably why the younger sister seems to be the leader.
In ViVid, Nove has eventually lost her angry attitude, but is still serious and more mature, and additionally has the responsibility to train the main characters while Wendi hasn't changed much.
The strong differences between Alicia and Fate is the reason why Presea abused the latter so much.
Kouichi Kimura and Kouji Minamoto of Digimon Frontier. Aside from being twins, the holders of the spirits of Light and Darkness, and having the entire Separated at Birth thing going for them, there's even an episode named "The Brothers Yin and Yang."
The Nitori siblings of Wandering Son couldn't be more different. Big Sister Maho is outgoing and pushy. Little Brother Shuichi is timid and feminine. This actually gets lampshaded by the pair's father, who relates to Shu a story of their grandmother betting Maho would be a boy and Shu a girl before they were born. Given the family's recent discovery of Shu'sissues, Nitori Sr. wonders if Grandma was really so wrong about them.
Ace and Luffy on One Piece. Ace is more level-headed and polite than his brash and bordering on brain-dead little brother. Even Luffy's crew have expressed disbelief at how different Ace is from their captain.
It has been revealed, however, that Luffy and Ace aren't actually blood siblings. They were raised together by Garp and consider each other as brothers, so they still count.
Fran and Veronica Madaraki of Franken Fran were outright made to be this. Fran was made to preserve life (which can lead to unpleasant results); Veronica was made to end it (which she prefers to do swiftly and painlessly, though often gratuitously). Fran tries to put Veronica more on her side of the scale, but so far, no dice.
And then there's Big Sister Gavrill, who's Chaotic Evil (she can shapeshift into a giant wolf-thing), unless she's giving practical advice as Fran and Veronica's high school guidance counselor.
Umehito Nekkozawa and his younger sister Kirimi from Ouran High School Host Club. He's dark, brooding and extremely photosensitive, while she's cheerful, outgoing, and hates dark places.
The twins have some of this as well, although only when they are separated. Hikaru keeps the trouble-making personality (with some added Tsundere) whereas Kaoru is much more mature.
Black and White of Tekkon Kinkreet. Black is violent and territorial and White is childish and innocent. The fact that they need each other to balance out the pair is repeated often throughout the film and becomes a plot point.
They're not actually related, but Tengen Toppa Gurren Lagann's Simon and Kamina were definitely designed to fit the trope — Simon is shy, relatively sensible, quiet and intelligent, where Kamina is outgoing, reckless, big-mouthed and something of an idiot. Their respective appearances couldn't be much more different, either; Simon is short (prior to the Timeskip, anyway), pale and skinny with dark purple hair and blue eyes, where Kamina is tall, tan and muscular with bright blue hair and red eyes. Finally, in case all of that wasn't quite unsubtle enough, their names also contrast: Simon's name comes from "shimo", the Japanese word for "below", and Kamina's name comes from "kami", the Japanese word for "above".
Amanchu! has Ai and Makoto, the former being a somewhat violent Genki Girl in contrast with her meek, thoughtful twin brother.
Both leading families of B Gata H Kei have this dynamic. Yamada is an energeticCovert Pervert who has little on her mind but sex. Her younger sister Chika is much more level-headed. Takashi Kosuda is shy but thoughtful, expressing himself through his camera. His older sister Kazuki is outgoing, boyish and shameless within her own house.
Raoh and Toki from Fist of the North Star: one of them is a merciless conqueror and the other is a messianic healer.
The Sasuke and Itachi dynamic plays with this. As a child, Sasuke strived to be like Itachi to earn recognition, but his brother was always several steps ahead. After the Uchiha massacre, Sasuke tried to distance himself from Itachi and become different from him, even refusing to obtain power in the same way as his brother. However, after Itachi's death, Sasuke drastically changes, becoming driven by hate and revenge against anyone who would stand against him, unlike his brother, who was motivated by love, albeit in a twisted way. Ironically, Sasuke would have ended up very similar to Itachi, had the latter not traumatized him in the way he did.
The First and Second leaders of Konoha were the Senju brothers: the elder was a laid-back, almost goofy straight-haired brunette who wanted to make peace with the Uchihas while the younger was a Combat Pragmatist with spiky white hair who thought it would be safer to just kill them all (their middle brother had both types of hair, split down the middle, but was killed before he reached adulthood).
Future GPX Cyber Formula has Osamu and Asuka Sugo. Osamu is a calm, level-headed individual while Asuka is more energetic and cheerful. Franz Heinel and his younger sister Lisa counts as well, with the same personalities as Osamu and Asuka has.
Unsui and Agon of Eyeshield 21. Unsui is serious, responsible, hard working, and polite. Agon is arrogant, self-centered, sadistic, and lazy.
Masao and Sanae Kouda from Detective Conan look nothing alike. Sanae is a pretty Office Lady, Masao has a huge case of Face of a Thug. Despite this, the siblings are very close... so when Sanae is killed by Watanuki, a man in debt that she was visiting for work reasons, Masao goes Knight Templar Big Brother and decides to prove it at all costs. Even by robbing a bank and hiding his loot near the man's backyard to force the police dig in so they can find Sanae's corpse.
The Suzuki sisters, too. Older sister Ayako is a soft-spoken and mature Ojou, younger sister Sonoko is an outspoken fashionista.
Infinite Stratos has the Shinonono sisters, Tabane and Houki. The older is very silly, while the younger is very serious.
Kotetsu and Muramasa Kaburagi from Tiger & Bunny. Kotetsu is an impulsive, Hot-Blooded, dorky Ascended Fanboy superhero, whereas Muramasa is his down-to-earth, low key, responsible older brother who runs the family liquor store.
Gundam AGE has Zeheart Galette and Desil Galette. Zeheart's a pretty nice guy & cares about his friends despite his loyalty to Vagan. Desil on the other hand is an Ax-CrazyBlood Knight who views soldiers, for Vagan and the Earth Federal Forces, as his own toys.
Bakusou Kyoudai! Let's & Go!! has a titular Seiba siblings. The older brother, Retsu, is level-headed and careful while the younger one, Go, is Hotblooded and reckless. Their traits show in their representative racing machines.
Rogue and Sting from Fairy Tail (who might not be related but were at least raised as brothers) are big on this. Sting uses 'white' magic, is always very in your face, shows interest in almost everything going on, and is only concerned with strength. Rogue uses 'shadow' magic, generally lets Sting do the talking, acts uninterested in evverything, and places value on comradery.
The biological siblings in the shogi manga Sangatsu no Lion had different reactions when a young shogi phenom entered their household and took their place in their obsessive shogi-master father's heart (shogi is everything to him and they just weren't talented at it): the brother became increasingly passive and played video games all day while the sister became a vicious bully who terrorized her foster-brother at home — and possibly in bed. As young adults the foster-brother (who's still/barely present in high school) lives alone because he didn't want to destroy their family like a cuckoo chick; the brother is a divorced loser, and the sister, who is "as beautiful as a demon" is dating her father's and foster-brother's Jerkass shogi rival, who also happens to have a hospitalized wife and young child.
In Dragon Ball, we have Son Gohan and Son Goten. Goten is very similar to his father, being naive and energetic. Gohan is the smart and polite son. Goten is also a borderline Blood Knight while Gohan dislikes fighting except in his SSJ2 form. Chi-chi actually trained Goten how to fight after Goku's second death and he lived in a peaceful world before Buu was released. Chi-Chi forbid Goku to train Gohan until the Cyborg/Android saga, one aspect why he dislikes fighting at the beginning. For Goten, fighting is fun when he was still a kid while Gohan experienced the deaths of people and his friends getting hurt while he was too weak to help them until the Cell saga, and he hates killing. Goten never experienced battles to death like his brother until Buu's arrival. However, ten years later, Goten has lost his borderline Blood Knight attitude and is more interested in girls, another contrast to his older brother, who was appearently Oblivious to Love and married his first girlfriend.
Son Goku himself is a Nice Guy and Spirited Competitor who dislikes wanton killing and he would never harm innocent people. His brother Raditz is a cruel Dirty Coward who enjoys killing and routinely liquidates entire planets for money. They are both like and unlike most other Saiyans in completely opposite ways.
The eponymous main character is friendly to others, with a shy and nervous side that often comes up. Her older sister Teru is confident yet embittered
Kuro Matsumi is outgoing and cheerful, although said confidence takes a blow when she goes up against strong opponents and loses points. Her older sister Yuu is a shy, timid Ill Girl, who nevertheless can become especially determined for the sake of her younger sister.
Charles Xavier and Cain Marko in X-Men. And that's before you get into how they are, respectively, the most mentally powerful and the most physically powerful people in the world...
Xavier also has Cassandra Nova, who exists to be his polar opposite in absolutely everything.
Batman's two sons, Tim "Robin" Drake (adopted) and Damian al Ghul (biological), in recent comics. Tim is logical, cool-headed, and always follows Batman's example by never killing, while Damian is rash, violent, and thinks nothing of killing his enemies. They slug it out every time they meet.
You could extend that to Tim Drake and Nightwing (Dick Grayson). Nightwing can be logical, but he's more hot-tempered and his creation of 'Nightwing' directly extended from him rebelling against Batman. Tim and Dick act like actual brothers though, unlike Damian.
And then there's Dick Grayson and Jason Todd. Apart from the obvious (Dick is a hero, Jason is a villain, or at least a Nineties Anti-Hero), Dick is acrobatic, fairly cheerful for a member of the Batman family, and indepedant from Batman. Whereas Jason relies more on weaponry, is dark and wrathful, and is almost pitifully obsessed with being seen as Batman's son true heir, if not replacing the Dark Knight himself.
The (otherwise unnamed) Two Brothers from Marvel vs. DC - one was the Living Embodiment of the Marvel Multiverse, the other was the Living Embodiment of the DC Multiverse. When they became (re)aware of each others existence, they each decided to destroy the other. They made up in the end, because Status Quo Is God.
Desire and Despair. Death and Destiny. Destruction and Dream. Delirium and... You know what, it's probably best just to leave it at: "The Endless".
Delirium and Delight.
Many examples in ClanDestine. The most prominent example is Jasmine / Cuckoo / KayCera and WalterDestine / Wallop. Then again, when their younger sister Samantha complains about their constant bickering, their father Adam attributes it to them being too alike. In a flashback, we also have Thaddeus and Albert, who seem to get on much better.
Ian (Ewan McGregor) and Terry (Colin Farrell) in Woody Allen's Cassandra's Dream. Even just visually, the contrast between the brothers is striking, looking nothing alike axcept for being drop dead gorgeous.
Happens naturally in Thor between him and Loki. Thor was a Boisterous Bruiser who took in the attention without realizing how self-descructive and reckless he was. Loki was the opposite, being quiet and prefers to use trickery and illusions to fight. Thor's character developments showed that he learned to stop, listen, think and be humble. Loki learning to fight, to take control, assert himself and manipulate others was his development to becoming a villain, completely opposite way of Thor.
In Secondhand Lions, both Hub and Garth are Badass Grandpas who had many adventures in their lives, but in the end, Garth is the more calm, bookish one who could sit back an relax while Hub was looking for adventure and had no trouble beating up five punks after getting out of the hospital.
Downplayed in The Prestige with the Borden twins. We don't see much of them as individuals, but one is a family man who loves their wife and daughter, and recommends just letting the rivalry with Angier die. Meanwhile the other is more aggressive, loves their assistant/mistress and sneaks into Angier's performance to learn how he performs"The Transported Man".
In La Piel Que Habito (The Skin I Live In), we learn that Robert and Zeca are brothers, with one child being bright and obedient and growing up to be a famous doctor, and the other going off to deal drugs at age seven and turning out as a killer and robber. However, by her own admission, they are both monsters, they just expressed it in different ways.
Elsa and Anna in Frozen. Princess Anna is cheerful, extroverted and a Badass Normal while Queen Elsa is stoic, introverted and very powerfully magical.
The sisters Houseman in Dirty Dancing — flirty, empty-headed Lisa and studious, altruistic Baby.
In X-Men: Days of Future Past, ten years after First Class, Charles and Raven have not only become estranged but also polar opposites in almost every way, especially in regards to ideology and diplomacy. Her sparing of Trask and the president shows that Raven isn't quite as far gone as originally believed, though.
Discworld: Esme and Lily Weatherwax. Granny Weatherwax is the angry, bitter old woman who always saves the day because she feels she has to since her "good" sister Lily ended up being the evil one. It's especially frustrating to Esme because Lily isn't even particularly good at being evil - in large part because Lily doesn't even realise that's what she's being.
Princes Peter and Thomas in The Eyes of The Dragon by Stephen King (Peter is fit and raven-haired like their mother while Thomas is chubby and sandy-haired like their father).
Fablehaven has Kendra and Seth Sorenson. Kendra is smart, cautious, and thoughtful, Seth is arrogant, energetic, and brave to the point of stupidity.
Most sibling relationships in Harry Potter follow this to some extent, such as Sirius (hates his pureblood-obsessed family and eventually runs away from home) and Regulus (proud to be part of said family), Bellatrix (fanatically devoted to Voldemort) and Narcissa (secretly terrified of him), et cetera. Also, Harry's mother Lily (a muggleborn witch) and her sister Petunia (who is perfectly normal, thank you very much).
In even greater contrast to Bellatrix and Narcissa is their other sister Andromeda Tonks. Not only did she not become a Death Eater, she married a Muggle-born wizard, produced a daughter who became an Auror, and helps out the Order of the Phoenix, though she's not officially a member herself.
The Izzies from The Merlin Conspiracy by Diana Wynne Jones play with this trope. At any given time, the two girls will take on polar opposite traits, for example one being rude and aggressive while the other is shy and fainting. Then, at random times, they'll switch roles. Twin girls in a magical family where only one can be selected to inherit the family's magic, this is their way of fighting back by making themselves completely indistinguishable.
Elinor - the sense - and Marianne - the sensibility, an archaic word for romanticism, in Sense and Sensibility.
Also in Austen, Pride and Prejudice contrasts intelligent, aware, Elizabeth with her pretty but vain and shallow sisters Kitty and Lydia, who are also compared to Jane, who is beautiful but also extremely sweet and loving, and all of the sisters are compared again with Mary, who is plain, austere and studious, yet stupid.
Persuasion fatures radically different Eliot sisters, Anne being friendly, pleasant, and down-to-earth, and her two sisters being selfish hypochondriacs.
Most prominently seen in Sansa and Arya Stark, who are each other's complete polar opposites and, as such, never get along. They even look completely different (Sansa is a beautiful redhead like her mother, Arya is plain-faced and darkhaired like her father.) Interestingly, their older brothers Jon and Robb have this too (Jon looks like Arya, while Robb looks like Sansa) but are extremely close in contrast.
Jon was slender where Robb was muscular, dark where Robb was fair, graceful and quick where his half brother was strong and fast.
Also, the vicious Joffrey Baratheon and his gentler little brother Tommen.
Also, Stannis (plainer, stricter, more honorable, and not good with people) and Renly (flashy, charismatic, handsome, a Sleazy Politician) Baratheon.
The twins Jaime and Cersei Lannister seem to be very similar in A Game of Thrones, but when they start getting PoV chapters and character developement in the later books, they move towards this trope. It's particularly in terms of how much morality (and sanity) they retain in any given situation.
Jaime and Tyrion are highly contrasted as well. Jaime is tall and handsome, Tyrion is a hideously deformed dwarf. Jaime thinks with his feelings and is a skilled swordsman, Tyrion is incredibly manipulative and fights with his wits. It was said that Jaime was the only one who gave a crap about his younger brother, in fact.
Staying within the Lannisters, Tywin Lannister was born to lead, Kevan Lannister born to follow. Luckily for them, they were born in the right order.
Song of the Lioness's Alanna and Thom. Alanna is a Hot-Blooded tomboy who enjoys fighting and friendship and (at first) fears her magic. Thom is a bookworm who wants to be the most powerful mage and shuns friendship because he thinks it's beneath him.
And in the Circle of Magic series, we have Daja's students, identical twins Nia and Jory Bancanor. Nia is shyer and quieter, with woodworking magic, while Jory is louder and more outgoing, with cooking magic. They actually get along quite well, though.
Leafpool and Squirrelflight in Warrior Cats. Leafpool is calm and patient, while Squirrelflight is hot-tempered and hyper. One character even compares them to water and fire when talking about their differences.
In Ayn Rand's Atlas Shrugged, we have Dagny and James Taggart, and Hank and Philip Rearden. Both sets of siblings hold polarized world views and that in turn shows us that blood is not Thicker Than Water.
Katniss and Primrose Everdeen in The Hunger Games. Katniss is tough, a tomboy, a hunter, has difficulty connecting with people, and resembles their father. Prim, meanwhile, is delicate, sweet, well-liked, a healer and Friend to All Living Things who resembles their mother. Despite this, the two are incredibly close.
Annie and Lila Little Hawk in Gives Light. Annie is thoughtful, quickwitted, feisty, and good at cooking and crafts. Little sister Lila is a glutton, a precocious flirt, and a mouthy brat.
Because they both reacted in very different ways when Alderaan and their family was destroyed, Tash and Zak Arranda of Galaxy of Fear ended up diverging more. Both are curious kids, but Tash is more withdrawn, empathic, and thinks she has to take care of her brother, who has become more of a daredevil.
Xiaohui wants to share Palimpsest with as many people as possible. Her brother puts a lot of effort into keeping any hint of Palimpsest off public forums.
Isabelle and Alec Lightwood from The Mortal Instruments. Isabelle is not averse to showing off her beauty, is generally nicer, and like Jace, always rushing headfirst into demon-slaying. Unlike her, Clary notes that Alec is shyer, easier to guilt, and tries everything he can to downplay the good looks he shares with his sister.
It's implied that Isabelle is the way she is in part because she wants to draw attention from her brother's homosexuality, as she does not want her parents to find out when he wasn't ready.
From Ender’s Game: Ender's brother Peter is the aggressive, masculine Yang to their sister Valentine's passive, feminine Yin. Peter was rejected from Battle School because he was too prone to violence, while Valentine was rejected because she was too compassionate. Graff tells Ender he has to find the balance between these two emotions in order to be an effective commander.
Hiro and his older sister Kimiko, with Hiro being idealistic, child-like, and bored by the prospect of being a businessman like his father; Kimiko is intelligent, motivated, and ambitious in regards to taking a place within the family's company.
The Winchester Brothers contrast in many different ways. Dean is loud, boorish, slutty and is a Big Eater in a nutshell. But he goes quiet (and even mute in fanon) when hurting, turns all his angst in on himself and his whole life is wrapped in Samand his family. Sam is mostly celibate (because of that pesky Cartwright Curse), is never shown to be eating and tends to be the quiet one while Dean takes control. But he gets louder and more dangerous when he's upset and his main Fatal Flaws are Pride and self-absorption. And he's far more independent than Dean, showing signs of wanting to flee the nest through the entire show's run, and, unlike Dean, would probably be able to go on permanently with his life if deprived of his family and hunting. The sex scenes (Dean in "Route 666" and "Heaven and Hell," and Sam in "Heart," "I Know What You Did Last Summer," and "Sex and Violence") show a difference between them too. Sex is fun for Dean; he doesn't mind being pushed down on the bed and letting the woman have her way with him. But for Sam, it's violent, kinky and it's clear he has to be the one in control and dominating. Sam and Dean's relationship is a parallel for Michael and Lucifer's, who are ying yang brothers themselves.
It's made clear that Sam and Dean's differences stem from their contrasting rolesin the family. Dean was forced to be his father's obedient solider and his brother's caretaker while Sam seem to have been allowed some measure of freedom and innocence. It's revealed for example that a lot of Dean's mannerisms were inherited from his father, thus making it also very likely that Sam's personality is a deliberate attempt to distance himself from his family.
Castiel has this with his brothers Gabriel and Balthazar.
Aunts Lily and Vivian in Pushing Daisies are both eccentric shut-ins, but the similarities end there: Vivian is gentle, flighty, and more emotional, while Lily is sharp and snarky, clever, and keeps her soft streak well-hidden.
The Booth brothers from Bones - Booth the elder likes his comfort zone while Booth the younger is flashy and much more upwardly mobile. Dr. Sweets observes that this dichotomy is not atypical in victims of childhood abuse. Seeley took on the role of serious protector while the younger Jared took on the role of attention-seeking trouble-maker, both in response to their father's physical abuse of them and their mother. One episode was essentially an in-universe Alternate Continuity short-story being written by Dr. Brennan. In this version the brothers' personalities remain largely the same, except their roles as protector and trouble-maker are switched with Seeley as a flashy nightclub owner and Jared as a straight-laced police detective.
The Girls and the Boys from Jon And Kate Plus Eight (the somewhat bossy Girls take after their mother while the more laid-back Boys take after their father)
Firefly: The Tams. Simon is cooler and calmer and more disciplined, and River is more sensitive and (for obvious reasons) more erratic. On the other hand, she is physically more powerful.
NUMB3RS: Don is more "Jock-like" and Charlie is more "Geek-like".
Dick and Beaver on Veronica Mars. Dick is loud, stupid, sex-obsessed and borderline-sociopathic. Beaver is quiet, smart, reclusive and actually sociopathic.
The twin brothers in the "War Zone" episode of The Closer. One's an accomplished Army Ranger, the others a gangbanger.
Jake and Ben Brockman in Out Numbered. Ben is outgoing, wild and wrecks chaos throughout the family, Jake is quiet, serious and often acts as a peacemaker. One of their teachers doesn't even believe they're related.
Mad Men: Anna Draper, widow of the real Don Draper is free-spirited and warm. She has a sister who is sour and uptight.
Vicki, a troubled girl addicted to drugs and Matt, a down-to-earth, normal Nice Guy.
Elena, a friendly, relatable Girl Next Door and her angsty Troubled, but Cute younger brother Jeremy. This was mostly prominent in early seasons, but averted later on the show, especially after Elena turns into a vampire.
From the new BBC Sherlock, the Holmes brothers are portrayed this way. Sherlock is easily bored and has a tendency to be incautious and oft-dangerously short-sighted when in pursuit of a solution to whatever mystery happens to take his fancy. Mycroft runs a shadowy government agency and is much calmer and more collected than his dramatic, wild brother. This is in contrast to the characters of the original books, where Sherlock was driven and really cared about what he called "his art," while Mycroft was terminally lazy and probably could have been even greater than his brother, except that he didn't care to be.
Identical twins Katie and Emily Fintch from Skins at least in their first season. Katie is the leader, dresses like sex-on-legs and Really Gets Around ("I haven't not had a boyfriend since I was seven"). Emily is eternaly in her shadow, dresses slightly more conservative, and falls in love and is monogamous. There is also the tiny little fact that Emily is a closeted Lipstick Lesbian and Katie is a raging homophobe whose favorite target is the girl that Emily has fallen for.
Charlie and Alan Harper from Two and a Half Men. One drinks, gambles, attracts the hottest women like moths to a bulb, and lives in a nice house overlooking the beach, while the other doesn't drink (on his best days, anyway), is socially awkward, and is hopeless with women... Oh, and he's also divorced, has a kid, and lives off his brother.
Cain and Abel. Abel loved God and gave him the best of his flocks as part of a sacrifice, while Cain's heart was not really in to serving God and he murdered Abel out of jealousy.
The Otterloop kids in Cul De Sac. Alice is a hyperactive attention seeker. Petey is anxious and quiet.
In FoxTrot, Peter and Paige are rather average teenagers, while their little brother Jason is a nerdy Child Prodigy.
The Unconquered Sun and Luna, from Exalted. One is so absolutely perfect and virtuous that he imposes order on the world by his mere presence, and the other embodies chaos and change to such an extent that she doesn't even have a consistent motivation. Polar Opposite Twins indeed.
A few of the Primarchs of Warhammer 40,000 have this dynamic, such as Leman Russ (a boisterous, superstitious, hard drinking Space Viking) and Magnus the Red (a sorcerer who was fascinated with knowledge and the mystic arts).
Iris and Colonel of Mega Man X4 are technically identical twins: as a developing single reploid, they couldn't handle the series' thematic Logic Bomb and split into Iris, compassion for all living things and Colonel, the willingness to kill without hesitation to protect and for peace. They were an attempt to replicate the titular X's ability to handle this paradox. They fact they failed to live up to these principles, even one at a time, causing Zero to have to kill Colonel and then a grieving Iris to combine their power, attack Zero, and also have to be killed may have originally foreshadowed that X would eventually no longer be able to handle the Logic Bomb himself - Copy-X of Mega Man Zero was originally intended to be an X who had lost that compassion and reluctance to kill and become a Knight Templar that Zero would have to kill.
Bethany and Carver Hawke from Dragon Age II definitely count, with the twist that you hardly ever see them together - one of them dies in the first half-hour depending on Hawke's player class. Bethany is kind and supportive of Hawke, whereas Carver is surly and shares a rivalry with Hawke. Bethany feels burdened by her magic and would rather be normal, while Carver is desperate to prove himself. From the same game, Varric and Bartrand - one does everything he can to subvert dwarf stereotypes, the other is obsessed with his ancestry.
Yun and Yang from the Street Fighter III series. Yun is loud and outgoing, while Yang is quiet and introverted. Also, Yun focuses on the strength of his attacks, while Yang focuses on the number of hits.
The three Pegasus sisters are a rare trio example. Quiet, serious Fiora butts heads with boisterous Farina, who in turn gets a kick out of teasing both her and shy, sensitive Florina.
In Fire Emblem 6 we have another sibling trio... also of Pegasus sisters. Yuuno is a sweet Action Mom, Thite is a stoic Defrosting Ice Queen and Thany is a hyper Genki Girl. And there's also a set of twins: the cheerful mage Lugh and the snarky shaman Rai.
Micaiah and Sanaki have some of this going on Radiant Dawn, though they do have their similarities. The former is a peasant until the end, the latter is an empress. The former possesses the Darkness affinity, the latter, the Light affinity. Both are kind and polite, though the former is often more soft-spoken wilst the latter can be a bit childish at times. Both, though especially the former, can be quite sarcastic at times. Both will do whatever they can for their country, though the former will demonstrate this to the max. They also both have a magic type in common. Their resemblance becomes even more apparent to anyone who bothers to compare images of their portraits side-by-side. About the biggest difference between them is that Micaiah will live far beyond Sanaki's lifespan because of being a Branded.
Fire Emblem Awakening has this between Chrom, Lissa, and Emmeryn. The sibling set-ups for the future children allows for this as well, depending on who is either Morgan's older sibling or Lucina's younger siblings: the most blatant examples are Lucina and Cynthia (if Chrom marries Sumia), or girl!Morgan with either Laurent, Gerome or Noire (if a male Avatar marries Miriel, Cherche or Tharja.)
Unusual triplet variant, from Metal Gear Solid - Solid and Liquid Snakes are extremely diametrically opposed; reserved, guilty Solid lacks his brother's ambitious, manipulative nature, and passionate, vengeful Liquid lacks his brother's wisdom and emotional clarity. This is complicated by the arrival of the third triplet, the calculating, focused Solidus, who considers himself a 'perfect balance' of his brothers' traits - he's wise and manipulative at once.
Hisui and Kohak in Tales of Hearts. The elder is Hot-Blooded and impulsive and rude, and his speech is crass; his sister is soft-spoken and polite. There's also Croaseraph, who is an aggressive Dual WieldingGlass Cannon who wants to Destroy All Humans!, and his brother Crinoseraph, a stoic, defensive spellcaster with two shields who's maintained his loyalty to his master.
Ronny and Sally Dobbs of Backyard Sports. Tony and Angela seem like this, but they're both egotistical.
The Williams sisters from Tekken. Nina is statuesque, cold, and blonde while Anna is the curvaceous and flirty brunette.
In Apollo Justice: Ace Attorney, Kristoph Gavin is a cool, businesslike defense attorney while his brother Klavier is a wild, extroverted prosecutor. Futhermore, Kristoph is evil and Klavier is good.
And in the same game, there's Apollo and Trucy, the protagonists themselves, although they don't know they're half-siblings. They do have some similarities, but Trucy is optimistic, a little naive, and extroverted. Apollo, on the other hand, is more cynical, sarcastic, and is more reserved around people than Trucy is.
Itsuki and Sayo in Suika. Itsuki is gentle, shy and a bit of a pushover. Sayo is brash, slightly tomboyish and aggressive.
From the Nasuverse, Shinji and Sakura in Fate/stay night. Subverted in that they aren't blood related. Sakura and Rin are, though, and also fit this trope. Sakura's powers match her side nicely, to boot.
Invoked in El Goonish Shive by Elliot's Opposite-Sex Clone, Ellen. Because she wants to break away from Elliot's person, she deliberately acts outgoing and flirty, while Elliot himself is reticent and prudish.
In PreTeena, protagonist Teena is a good-hearted and cheery Tomboy. Her sister Jeri is a cold-hearted and moody Girly Girl. Teena also still wants to be a good student in school, while Jeri doesn't care about that anymore.
It's complicated to explain the relationships of kids of Homestuck, but they seem to do this:
Brunettes (John and Jade Guardians/Alpha counterparts Jake and Jane): Naive, Adorkable with Nerd Glasses, forthright, and Jumped at the Call. John and Jane live in the suburbs while Jade and Jake live on isolated islands. John, Jade, and Jane have like certain genres more than others (bad movies (unironically), furry art/anime, and comedy, respectively) while Jake loves all genres indiscriminately (but specially if they have blue-skinned space babes).
Blondes (Rose and Dave Guardians/Alpha counterparts Roxy and Dirk): Cynical, slightly Anti-Hero with Cool Shades for the guys and Scarf Of Ass Kicking for the girls, Genre Savvy/Properly Paranoid. Rose is the hero of Light and dislikes alcohol at age 13 while Roxy is the hero of Void and is a 16-year-old Hard-Drinking Party Girl (this is later reversed: Roxy wants to be sober while Rose discovers the joys of drinking); Dirk is always awake (he's simultaneously awake in the real world and in the dream world) while Roxy is always intoxicated (she's drunk in the real world and sleepwalks in the dream world).
Their guardians are also their ectobiological siblings, but the yin-yang shows up most in Rose/Roxy and Dave/Dirk, who are always wondering if their guardians are being ironic/sincere (Dave is ironic; Dirk is a little bit more sincere) and cruel/playful (probably not cruel but Rose thought her mother was playing a game of "passive-aggressive oneupsmanship" by doing over-the-top things like having a lavish funeral for her pet cat while Roxy, who'd never been to a funeral, genuinely wanted to see what one was like and it's probable as "Mom Lalonde" she felt the same), respectively.
In as much as animal counterparts can be considered siblings: Bec is the "good dog, best friend" of his owner Jade while God Cat is owned by no one and seems much more ambiguous. They're the omnipotent guardians of the Earth, manipulators of sapient beings, and masters of a game that will create a new universe from the ashes of the present one — or would be if they weren't just animals with super powers. Well Bec definitely was, GCat's still a mystery.
The Troll kids (who are siblings) do this with their ancestors and each other. For example Vriska likes to torture the child-like Tavros and while they're both considered losers their ancestors were a hugely successful pirate queen and an almost-successful messiah-figure.
Since Strong Mad and Strong Bad of Homestar Runner were originally created based on a wrestling tag-team, they both have brash personalities. Their brother, Strong Sad, however, is creative, sensitive, and depressed.
Bart, a lazy delinquent, and Lisa, a socially-aware academic, in The Simpsons.
Carl and Herman, with Carl's magic and strategy being contrasted by Herman's muscle and brute force. "Dojo Alone" showed that, if they ever worked together, they'd be unstoppable, but they can't stand each other.
Yin and Yang coping with each others' differences is quite a major part of the series. While Yin is studious, feminine, and a magic user, Yang is rather idiotic, rough, and prefers to use might over magic.
Danny and Jazz in Danny Phantom. Danny is insecure, rash and powerful, while Jazz is book-smart, confident and collected.
Mako and Bolin grew up on the streets, but while Mako is a broody, dark, Troubled, but Cute firebender devoted to winning the probending league and protecting his little brother; the other's a boisterous, fun-loving, earthbending lady's man.
Tenzin has this relationship with his siblings Kya and Bumi. When they were children Tenzin was very serious while his siblings were rather rambunctious. In the present we've seen that Tenzin is serious (usually), bald, and monk-like while Bumi is "a wild man" in the armed forces of the United Republic with a head full of anime hair; meanwhile Kya is unmarried and traveled all over the world to "find herself" (which Tenzin saw as abandoning her family) while Tenzin settled down and had a large family. Tenzin and Kya are benders with a spiritual/healing, while Bumi is a Bad Ass Normal military man/walking disaster area.
Between Korra's father Tonraq and her uncle Unalaq. The older brother, Unalaq is ambitious, focused on spiritual concerns, and feels driven to lead his people; while the younger brother, Tonraq is unambitious, focused on physical strength, and decidedly unspiritual.
Lin and Suyin Bei Fong. Lin highly values law and order, never wanted childen and is generally very cold, serious and bitter. Suyin on the other hand was a teenage rebel, still does not like authority too much, but highly values family, having five children of her own, and appears to be rather warm and open towards other people.
Yin and Yang from the Histeria!! episode "Return to China".
Phineas and Ferb, in some ways, though their differences seem more complementary than opposed, given how close they are. (Technically they're stepbrothers, though even they never refer to themselves that way.)
For that matter, either/both of them with their older sister Candace.
Princess Celestia and Princess Luna. Celestia, who controls the day, is gentle, motherly, and a bit mischievous, while Luna, who controls the night, is stern, overly formal, and a bit bad-tempered (as seen in "Luna Eclipsed"). That may be a side effect of being sealed in the moon for a thousand years, though.
The Powerpuff Girls have Buttercup, a tough angry tomboy, and Bubbles, a gentle Girly Girl, who almost never gets mad. Blossom is somewhere between them personality-wise, but she also is the most intelligent one.
Christopher and Peter Hitchens. Christopher was a very outspoken atheist/anti-theist and held predominantly (but by no means exclusively) liberal political views. Peter is an Anglican convert from atheism and holds predominantly conservative political views. Granted, both are relatively high-profile journalists, but beyond similar vocations and genetics, the similarities generally end there.
Chris was known for drinking and smoking a lot, whereas Peter can't drink much and doesn't smoke. Plus, Chris supported the Iraq War, bucking the left-wing consensus, whereas Peter opposed it, bucking the... Uncanny.
The Filipino brothers Juan and Antonio Luna. Juan was a painter while Antonio was a general and a chemist. Oddly, they both were good at fencing, and would often spar with each other. Antonio in particular was reputed to be so good that anyone who was not Juan would end up dead dueling him. They also both had a hot-blooded streak: Antonio's temper was so explosive that his men were scared of him (especially when his face contorted so much he got the nickname "Cafre" for it) and Juan, though calmer than his brother, murdered his wife and mother-in-law.
George W. and Jeb Bush. Both are Republican politicians, true, but George is (by all accounts) a very personable man who parlayed his youthful love for the bottle and a certain white powder into a deeply-held religious faith. Jeb (by all accounts) is somewhat less personable (though not half as detached as their father), and seems not to be half as religious as his brother. Oh, and one is seen as being rather stupid (although some see this as Obfuscating Stupidity), and the other is quite intelligent and certified political whiz.
Not so sure about Jeb not being so religious. He is a high ranking member of the Knights of Columbus.
The Knights of Columbus are Catholic. George W. Bush is a born again Christian. It's a different sort of religious attitude, even if there's an equal level of devotion involved.
The Mitford Sisters. Two of them were Nazis Diana (who married Oswald Mosely, leader of the British Union of Fascists) and Unity (a personal friendnote Rumor said lover; unlikely as it is, it seems that she wished she had been of Adolf Hitler, who called her "a perfect specimen of Aryan womanhood"). Jessica on the other hand was a member of the Communist Party and civil rights activist. Nancy was a novelist, and Deborah is the Dutchess of Devonshire; Nancy was considered to be a moderate socialist, and Deborah a moderate conservative. Pamela was the only non famous sister; in private, she seems to have been a typical Tory (albeit a bit more racist than was acceptable even for a conservative of her class and generation).
Al Capone, famous gangster who made his fortune primarily through the selling of alcohol in the Prohibition era, and his brother James "Two-Gun Hart" Capone, one of the most successful Prohibition officers of the era.