Ryoma from Prince of Tennis. A whole anime episode was dedicated to him sleeping in before the Saint Rudolph match and his friends trying to fill in before he gets to the courts.
Kyouya Ootori from Ouran High School Host Club. He's sometimes referred to as the "Low Blood Pressure Overlord" because of it. Also, Token Mini-Moe Hani has been known to beat up a soldier for waking him up too early.
According to an extra chapter in the manga, Mori becomes sociable and flirty when he's sleepy. Considering his character, it's hard to say whether or not this is being played straight.
A bonus story in a volume of D.N.Angel shows Satoshi's morning routine. It says that he gets up early in the morning and spends "half an hour wandering around in a daze" before he fully wakes up and gets ready for school. Again, the cause is given as low blood pressure.
Yuki from Fruits Basket, to the point that he often gets up and sleepwalks in the morning. His karate-trained reflexes are still in effect however, and he'll often swing punches at his rival in his sleep without being fully aware of it.
Nayuki from Kanon is this, as well as a Heavy Sleeper. She says that she got her spot on the track team because she often has to run to school in the morning.
In Azumanga Daioh, while the characters are on vacation at Chiyo-chan's summer home, Osaka wakes up and announces that she's going to wake Yukari up by banging on a frying pan. However, she's not yet fully awake herself, and the implement that she retrieves from the kitchen is a large knife, much to the shock of the other characters.
Yukari herself is not a morning person, often needing her mother or Nyamo to wake her up for work.
Asuna in Mahou Sensei Negima! is known for being bad at mornings (she gets up early on weekdays for her paper route, then sleeps in heavily on weekends).
Nabiki Tendō of Ranma ½ is portrayed as such, especially in the anime. It tends to be played up in fanfiction.
That might possibly be because she tends to get woken up at around the crack of dawn by the sounds of Ranma and Genma sparring. If my "alarm clock" was two guys audibly beating on each other, accompanied by insults and random battle cries, I wouldn't be particularly energetic either.
Naru from Ghost Hunt is not good when he wakes up. Then again, it's his fault for sleeping in a van (vol. 1) and being possessed by a spirit, to which Lin forces him to sleep with a series of spells and charms in vol. 8 to 9. Needless to say, he was not in a good mood when he woke up. Lin and Masako witnessed it first hand and they'll never be the same again...
Roger from The Big O has this problem, credited both to his character and to his late-night "negotiating". Other characters have repeatedly complained about his tendency to wake up past noon. Thankfully, Dorothy's there to play a little "Run Down" on the piano...
If Kyon's sister from Suzumiya Haruhi doesn't wake him up every morning with glomps, he'd most probably be late for school.
Misato Katsuragi from Neon Genesis Evangelion has this problem, even if she has not been drinking the evening before. Well, that and the fact she's incredibly lazy when it comes to household chores.
Funnily enough, the thing that gets her fully alert is...more beer.
Garfield: I'm not a morning person. Jon: Good afternoon, Garfield.
Roger Fox, the father of the household in FoxTrot, tends to be... rather incoherent before his morning coffee.
"Coooooffeeee...""The pot's over by the fridge." "Coooooffeeee..." "The fridge is that way." "Coooooffeeee..." "See that thing with the little red light?... Roger, that's the answering machine!" "*glug glug glug* "
Jeremy from Zits, as amply demonstrated by the image above. For those who are Not a Morning Person, what he is describing is familiar — that time between being rudely awakened by an alarm, and actually being able to get out of bed.
In another strip, he asks his mother to sign a note reading "Please excuse Jeremy from this morning's classes due to excessive gravity."
Scott Pilgrim qualifies, if only because there isn't much morning, if any, left by the time he wakes up.
In fact, the one time he does get up early, it's the first sign that something is wrong.
Batman, since he fights crime at night, tends to sleep in late and doze off during work meetings. This fits his cover as a Rich Idiot with No Day Job, so no-one thinks twice about it.
Basile from Léonard le Génie, when left to his own devices, will wake up at half past five... in the afternoon, and considers anything before noon the middle of the night. Leonardo tends to spend a lot of time and resources on just getting him out of bed at the beginning of every episode.
Emma Frost of the X-Men. She has specifically instructed her students (who, keep in mind, are knowingly being taught by a group of fugitives) to never wake her.
In Cerebus the Aardvark, getting out of bed is a massive struggle for Jaka's husband Rick, and even when he's finally up and moving he's slow and sluggish, with a tendency to drift right back to sleep as soon as he comes to a stop. Jaka can wake him in a hurry with a "wet willy", but he's back out soon after.
The opening shots of Shaun of the Dead feature dozens of Londoners shuffling zombie-like to work, pretty much all of them looking like they're Not a Morning Person. The actual zombies blend in rather well at first.
Princess Anna, in Frozen is shown having a lot of trouble waking up on her sister's coronation day.
Used very hilariously to show just how human-like WALL•E has become. When the titular robot wakes up in the morning, he stumbles around his trailer much like a person would: groaning, arms drooped, running into things, and fumbling for his "shoes" (his caterpillar tracks). He's not really "awake" until he has a breakfast of sunlight.
Nick Mallory in Diana Wynne Jones's Deep Secret/The Merlin Conspiracy is very much not a morning person. Not only is he grumpy, he can't even speak coherently or open his eyes until he's had four cups of coffee. It's later shown that he can wake up... he just feigns being really out of it so no one will bother him until he's less grumpy. Apparently, this is based off of Wynne-Jones' friend Neil Gaiman's actual morning routine.
Running gag in the Aubrey-Maturin books. Aubrey sleeps easily and wakes fresh as a daisy, while there's at least one book where Dr. Maturin is woken up to perform a vital surgery on a dying patient. His response? Cussing, throwing things and then refusing to go anywhere near the sick bay until coffee had been provided.
Stephanie Plum considers five in the morning to be the middle of the night. Most of her associates disagree, to her disgust.
In Child of the Hive, Will is oblivious to all of Alex's attempts to encourage him to wake up. When Alex then phones Ben, his reaction is, "Bugger off, 'm hungover."
Mike was a stout supporter of the view that sleep in large quantities is good for one. He belonged to the school of thought which holds that a man becomes plain and pasty if deprived of his full spell in bed. He aimed at the peach-bloom complexion.
"Tash, even secret Imperial plots don't get going until after breakfast."
A running theme pf the Garrett, P.I. novels is Garrett's intense aversion to hauling himself out of bed before noon, and his crotchety housekeeper's various ways of nagging, aggravating and/or threatening him into doing so. Made more ironic by Garrett's own need to hassle the Dead Man into waking up at any hour of the day.
Sam Vimes showed some signs of this, expressing some irritation at being woken up at 9AM when he normally doesn't get up "until the afternoon's had the shine worn off it" at one point in Men at Arms, but that's probably acclimatisation from spending most of his adult life working the night shift. Promotion to Commander of the City Watch brings more normal working hours... for a given value of "normal", and even that ended up being a Defied Trope.
The short-lived sitcom Pearl gave us this gem between Rhea Perlman and Malcolm McDowell:
Professor: Questions about ethics can be answered with one simple thing: a mirror. [...] After the fact, can you wake up the next morning, look into the mirror, and like what you see? Pearl: At what time in the morning? [...] 'Cos I've never seen anything in the mirror before 8 o'clock that didn't belong in a horror movie...
Father Ted generally will not start his working day until at least 11 am and frequently later. Consequently, being woken at 5am with an airhorn during Lent comes as something of a shock.
In Red Dwarf, the reason that Lister gave for not finishing college was that there were lectures at half past twelve every day.
Lister: Come on, who's awake then? You can still taste the toothpaste.
Penny in The Big Bang Theory. She has a "Don’t knock on my door before eleven o’clock or I punch you in the throat" rule.
The very first time we meet Anna, the senior housemaid on Downton Abbey, she's groaning and clutching a pillow over her head, grumbling about how she wishes she could wake up naturally just once in her life.
One first-season episode of Mystery Science Theater 3000 revealed that neither Joel nor Tom Servo likes mornings — in direct contrast to Crow, who does.
Crow: Hey, good morning, Breakfast Clubbers! Heh, heh, hey! How ya doin'? Hey, here's a little morning poem: "Birdie with a yellow bill, hopped upon my window sill, cocked his shining eye and said... what's for breakfast, Grandma?" Heh heh heh... Tom: ...Oh, I hate morning 'bots!
Neil: Lads? It's two o'clock in the afternoon. Maybe it's time we got up. Lucky I didn't sleep through the alarm or we'd have missed half the day!
When Tracy on 30 Rock goes through a brief phase of shaping up to make his wife happy, it includes getting up at a reasonable hour for apparently the first time in his adult life, but he takes to it okay. As he reports to Liz, "Did you know that in the morning they have food, TV, almost everything? It's pretty good."
I know this because I took economics. And I'd explain it to you, but I flunked that course. It wasn't really my fault; they taught it at eight o'clock in the morning, and there is absolutely nothing you can learn out of one bloodshot eye. After I flunked the first two tests, I grabbed the professor by the throat and said, "WHY ARE YOU TEACHING THIS SHIT AT THIS UNGODLY HOUR? ARE YOU TRYING TO KEEP IT A SECRET?"
GURPS offers the Slow Riser disadvantage, in which, for an hour after waking up, your character suffers -2 to self-control rolls and -1 to IQ rolls and IQ-based skill rolls. So, in other words, they're irritable and can't think properly. They also get an extra penalty for missed sleep.
In Vampire: The Masquerade, Kindred fall asleep earlier and wake up later as their Humanity degrades, and they generally can't use more dice than their Humanity score for any action while the sun is up. Particularly wicked Kindred aren't "evening people" at all.
There's also a cheap Flaw, "Late Riser", that has you wake up about an hour later than usual for Kindred. It's cheap because there isn't a real mechanical drawback, but you can expect to be late to most important faction business.
In Chez Geek the Slacker/Unemployeed job quote: "It's only 2 o'clock, they might not be up yet."
Though apart from the games' openings Link tends to qualify as The Sleepless.
Rin Tohsaka from Fate/stay night. She's not quite as bad as the other examples but tends to be decidedly grumpy in the mornings... Actually, it clashes with her perfect schoolgirl image so badly that even after knowing her for awhile, people are outright shocked to see her dragging about in the morning, completely at a loss for words and unsure if what they've just seen was real.
A Running Gag in Mega Man Battle Network is that it's nearly impossible to wake up Netto/Lan Hikari on time. On one occasion in the anime he woke up, assumed he overslept, then got all the way to school before realizing it was Sunday.
In Harvest Moon: Animal Parade, the Wizard is not a fan of mornings. Until a certain quest event, you can only meet him around or past 2 AM. He also loves coffee.
Grumpy-type villagers in the original Animal Crossing sleep in until around 10 in the morning, most days. In all games, they'll also gripe about it being early in the morning until around noon. New Leaf introduces Uchi-type villagers, who don't get up until 11:00 AM—and if you enter their house around that time, there's a good chance they'll still be asleep...
Lady Sialeeds from Suikoden V is generally a pleasant person to be around, but enjoys her sleep and gets rather, er, "cranky" when someone disturbs her. Servants will actually thank you for not making them wake her up, and poor Lyon wound up with a black eye one time after doing so.
Ayane from Dead or Alive Extreme Beach Volleyball remarks that she hates mornings, and if you give her a gift during the morning you'll earn less approval with her than if you give her a gift during the afternoon or evening.
Since Dechs "Shadehawk" Rashart — a.k.a. Antihero for Hire — habitually "works nights", he takes this to extremes. Forget mornings — waking him up before sundown has this kind of effect.
There's a Casey and Andy strip where Andy has made coffee — despite not drinking coffee himself. The question of "why" is answered when Satan enters — in the form of a seven-feet tall, winged, clawed, fanged, bright-red and particularly grumpy-looking demon. One gulp of coffee later, she reverts to her familiar form, brightly remarking "Morning, all!". "Yeah," comments Andy, "It's best if she gets her coffee right away."
In Knights Of Buena Vista, Mary gives her player character this as a flaw. The Game Master confuses this for oversleeping, but she corrects him. It does include bedhead for extra points though, which surprises fellow player Adriana.
Egon: Sounded like "get out of my face or eat flaming terror".
People who routinely stay awake during the night and sleep in the morning are usually stereotypically considered terminally lazy, but science now tells us they might just have delayed sleep phase syndrome.
This can be really common for theatrical actors and actors in general. They run really crazy hours because of rehearsals in theater and filming in well, film. Theatrical actors traditionally have night shows, therefore they are most alert and energetic at night when they preform. As a result it's very common for them to be Night Owls and not be all that big of fans of the early morning.
Lindsey Stirling is a morning person, but those she travels with definitely aren't. For Easter 2013, Stirling arranged an Easter Egg Hunt for everyone else on the tour bus. She was up bright and early setting out eggs, baskets, and a trail of footprints supposedly by the Easter Bunny, but trying to wake up those touring with her didn't quite go so well. They wondered at how she could do it given that they'd done a show the night before.