Adaptation Displacement: The 1995 miniseries to a certain degree, especially within the fandom itself. While everyone still knows it was a book first, the miniseries is so faithful that the instances of Fanon (e.g. the "shelves in the closet" joke) get frequently treated like canon.
A fair few feminist critics of the book posit Elizabeth as being just as materialistic as any of the less sympathetic characters by focusing on her feelings for Darcy changing as she visits his magnificent estate. (Considering that, during this retelling, Jane immediately thereafter entreats her to please be serious, these critics may have missed the mark, or at least the humor- especially as Lizzie may have referred to the fact that said estate was well-organized and full of servants gushing over Mr. Darcy, which indeed was a turning point for her.)
There are also some who wonder if Mrs Bennett really deserves as much scorn as Lizzy throws on her. While she's incredibly embarrassing, it should be noted that she's trying to make sure her daughters have a roof over their heads when Mr Bennett dies.
Some adaptations portray Mary in a much more sympathetic light, emphasizing her plainness and bookwormishness compared to her more attractive and outgoing sisters. Even amongst those who have only read the book, Mary has a sizable fanbase. The 2005 adaptation gives a few hints that she falls for Mr. Collins during his stay. The 1940 film ends with her being wooed by a clerk from the bookstore she is first seen in at the beginning of the movie - and he accompanies her on the flute as she sings!
Depending on the writer/director, Mr Collins ranges from "awkward and stupid but sincere" (2005 movie) to "probably some kind of sexual predator" (Lost in Austen). The 2005 version is actually truer to the original than many other adaptations, especially those that make him into a rapist. Austen was a rector’s daughter; she might poke fun at the clergy but Collins never gets any worse than stupid and overly conventional.
The 2005 adaptation in general softens the edge on most of the cast, giving Mr. and Mrs. Bennet a few Aww, Look! They Really Do Love Each Other moments, lessening Mr. Collins' sliminess, and presenting Mr. Darcy as shy, rather than snobby.
Draco in Leather Pants: Mr Darcy is an unusual example of this trope. The point of the story is to not judge by first impressions alone, and Elizabeth does discover that Darcy can be a genuinely decent and noble person once she manages to look past the unfavourable view she initially developed of him. However, many readers tend to extrapolate this to view Darcy as a borderline saint who was always completely misunderstood and perfect. In fact, Darcy himself admits that many of Elizabeth's initial criticisms of his character were, in fact, entirely justified — he genuinely could be a bit of a cold, unpleasant snob (albeit not nearly the hateful bastard that Elizabeth had convinced herself he was) and had to do plenty of soul-searching and improvement of his character in order to become a man worthy of her affections.
Even those that groan at reading the book, nay even some haters, love Mr. Bennet and his snark.
Charlotte and to a lesser extent Georgiana. Both are relatively minor characters, but they have distinct personalities and interesting dynamics with the other characters, so the fandom tends to pay more attention to them than they get in-story.
Epileptic Trees: Although not really present in the original novel, some later adaptations tend to run with the idea that Mary was secretly in love with Mr. Collins. However, unfortunately for her he was Oblivious to Love and too occupied in punching over his weight in chasing after Elizabeth to notice. Considering the personalities of the respective characters, this isn't an implausible idea even in the text of the novel: it is said that Mary appreciates Mr. Collins more than the rest, and there is a brief moment, after Elizabeth's rejection, when it is thought that Mr. Collins would propose to Mary, who was not opposed to the possibility.
In the director's commentary for the 2005 version, Joe Wright confirmed that Mary is in love with Mr. Collins but in his own words "he's too stupid to notice".
Fair for Its Day: Though Austen was hardly a socio-political radical, she showed a great deal of flexibility toward the idea of class, with several characters that subvert their societal roles. And while she suggested no alternative lifestyle choices, Charlotte's pragmatic choice and Lydia's bought-and-sold marriage rather bluntly illustrate the dependence and limitations placed on women of the time.
Fan-Preferred Couple: A lot of the fandom ships Mary/Mr. Collins instead of Charlotte/Mr. Collins, usually on the grounds that Mary actually would've been quite happy as a minister's wife, and since they're both bookish, wannabe intellectual Know Nothing Know It Alls, they'd have plenty to talk about. It's fanon that Mary has feelings for him, but Mr. Collins is just too dense to realize how perfect she'd be for him.
As noted above, some fans are convinced that Mary secretly has feelings for Mr Collins, and that she was hoping he would propose to her as the next sister in prominence after Lizzy turns him down.
Jane is commonly portrayed as a blonde, presumably due to the influence of the Hair of Gold, Heart of Gold trope. Her hair colour is never mentioned in the text, and she's not blonde in the 1940s film.
Since we learn very little about her other than she's sickly, some fans like to flesh out Anne de Bourgh. Popular interpretations are that she fakes (or least plays up) her illnesses as a way of coping with and avoiding her overbearing mother, and that neither she nor Darcy had any particular interest or desire to marry the other and that the whole "betrothal" was merely Lady Catherine seeing things that weren't there.
Harsher in Hindsight: Darcy buys Wickham a commission as an officer in the Newcastle regulars as part of his bribe to force him to marry Lydia. In real life the regiments stationed at Newcastle fought at Waterloo and suffered the heaviest casualties of any British troops; the officer corps in particular was killed off virtually to the man. Austen couldn’t have predicted this, of course, but had Wickham been real he wouldn’t have survived to plague the Bingleys.
Darcy's and Elizabeth's debate about the dangers and merits of yielding to persuasion — emphasis Elizabeth's.
The 1995 mini-series with Jennifer Ehle (Lizzy) and Colin Firth (Darcy) became this after The King's Speech, where Ehle plays the wife of George VI's (Firth) therapist. They have one scene together, where Ehle's character's eyes bug out over seeing the royal couple in her home.
In the 2005 adaptation, Carey Mulligan plays ditzy younger sister Kitty and Rosamund Pike portrays intelligent, if overly-trusting, eldest sister Jane. However, in An Education, Mulligan is Oxford-bound Brainy Brunette Jenny, while Pike plays Dumb Blonde Helen.
Also in the 2005 adaptation, Jena Maloney plays Lydia and Donald Sutherland plays Mr. Bennet... Jena plays Johanna Mason in Catching Fire, and Sutherland plays President Snow.
Another for the 2005 film - specifically Lizzy turning down Mr Collins. Repeatedly. In Pirates of the Caribbean: Dead Man's Chest the two actors star together, where Tom Hollander stops Keira Knightley's wedding and has her arrested.
In the 2005 version, the plain, bookish Mary is played by Talulah Riley... one of St Trinian's hottest Fille Fatales.
Charlotte averts this in the 2005 version (in which she is played by Claudie Blakley); while she wouldn't crack any mirrors and is fairly good-looking, her make-up and hair-does are rather low-key and she is not prettied up.
Charlotte Lucas (Lucy Scott) in the 1995 miniseries, however, is decidedly more attractive than her book counterpart.
While Elizabeth is by no means meant to be unattractive, Jane is universally considered the Pretty One. This can be slightly difficult to believe when she is played by, for example, Keira Knightley.
Ho Yay: Darcy and Bingley. Even Elizabeth notices.
It Was His Sled: The BBC America trailer for the 1995 miniseries starts by showing the wedding and stating "We know how it ends..."
Love to Hate: Wickham. Most of the fandom delights in trashing him at every opportunity, and justifiably so.
Memetic Badass: Elizabeth Bennet, of the Badass Pacifist kind. There's a reason the scenes where she turns down Darcy's first proposal and verbally destroys Lady Catherine tend to get remixed with epic music playing in the background.
A very common sentiment in the fandom: "When I was younger I thought I'd grow up to be Lizzy. I realize now that I'm Charlotte." Charlotte's quote about being a burden on her parents and having no prospects is often brought up at the same time.
"See? Deeply rooted dislike is always just a mask for true love!" Tell that to Mr. Collins. Not to mention, when Elizabeth is acting like she hates Darcy, it's not to hide her true feelings for him — she acts like she hates him because she does hate him, namely because he's being a jerk. When she realizes he's not a bad guy (and when he takes steps to improve his character so he isn’t the ‘bad guy’) she starts being more civil and eventually falls in love with him.
Mr. Darcy gets this to an extent — several of the people who swoon over and admire him tend to forget that he's not just a perfect and misunderstood romantic hero, and that Darcy himself admits that he was genuinely a Jerkass (albeit not quite to the extent that Elizabeth had convinced herself) and that he did genuinely deserve a large part of Elizabeth's condemnation of him.
Narm: The alternate US ending of the 2005 film. Especially the repetition of "Mrs. Darcy". It's meant to be sweet. It ends up being ridiculous and slightly creepy.
Narm Charm: Most hardcore fans will agree that the 2005 film is a flawed adaptation of the book — and, indeed, a flawed movie in general — but most will also agree that it's a fun, lighthearted flick and enjoyable to both book fans and newcomers, in spite of how silly it can get.
One True Pairing: A big one. Elizabeth/Darcy is one of the most universally beloved couples in all of literature.
Ron the Death Eater: As mentioned above, some modern-day critics seize on Elizabeth's comment that her feelings for Darcy changed after seeing his grand estate as evidence that she is selfish, materialistic and shallow — ignoring that, in context, she is clearly making a joke. Not to mention, in the book, when she first sees the estate, she comments to herself that it all could've been hers had she married Darcy... and then promptly reminds herself that she doesn't like him and considers him to be a massive prick, so she's glad she turned him down, estate or no estate. (There is also the fact that the gushing servants and obviously well-kept estate convince Lizzie that perhaps Mr. Darcy is not quite as bad as she thought and the letter in which he detailed his side of the Wickham story may be really true.)
The Scrappy: Lydia. Of course, you're not really supposed to like her, Lydia being a horrible, shallow Spoiled Brat and all.
They Changed It, Now It Sucks: The 2005 goes for The Dung Ages approach to the Bennets, where Longbourn is depicted as slightly shabbier than it was in the book. This is in contrast to the 1995 miniseries's clean, polished look.
Austen probably didn't expect Mary to get as much sympathy as she does. Of course, she probably also didn't expect her future readers to be living in a world that in general has a bit more sympathy for people like Mary — i.e. introverted, bookish types who don't like balls. Especially since Mary's living in a world where she has no option but to get herself a husband, whereas today's readers (many of whom happen to be introverted, bookish types) have far more options in life (not to mention, far more ways to meet people than Mary would) and can't help but sympathize with someone who doesn't have the choices they do. Yeah, Mary's a bit of a jerk, but she's not a bad person. It's hard not to feel a tiny bit sorry for her.
Lydia, though still viewed as obnoxious and unlikable, tends to get at least some sympathy from modern readers, since most would argue that no one deserves to be stuck with Wickham for the rest of their life, especially considering Lydia is fifteen. In Austen's time, Lydia getting married at that age would be considered to be a bit young, but still allowable and relatively normal. (Like getting married at nineteen or twenty in today's day and age.) Today, marrying a fifteen year old off to a known scumbag who's twice her age would be unthinkable. Most adaptations that are set in the modern day tend to give Lydia a little more sympathy, and often cut her marriage to Wickham altogether.
Despite Mr. Darcy instantly standing out as the richest and most handsome man at the ball when he first arrives in Hertfordshire, the ladies quickly lose interest because he's a haughty, brooding loner... which would only serve to augment, rather than diminish, his appeal today. Many a girl and many a woman swoons over Tall, Dark, and Snarky men. Which explains why so many women today are in love with Darcy. That attitude started with Romanticism, which was in its early stages by the time Austen was writing. It wasn't mainstream yet, but even Austen has characters who express those feelings, such as Marianne from Sense and Sensibility (which is all about Romanticism Versus Enlightenment, represented by Marianne and Elinor respectively).
Charlotte's quick marriage to Mr. Collins. She can't stand him as a person, but her prospects are so poor (she's the ripe old age of 27 and only average if not plain in looks with little money) and his are so good that she accepts; these values seem rather off-putting to modern female readers. This is lampshaded by Austen through Lizzy, who is appalled that her best friend would stoop so low just to secure her own comfort. Charlotte was Austen's commentary on the plight of the average woman during the Regency, who would sadly often sell themselves to the highest bidder in an effort to avoid ending up on the streets or worse.
Everyone's reaction towards fifteen-year-old Lydia running off with mid-twenties Wickham. Today, it would be more like "arrest that creeper!" But Lydia's family gets them quietly married so as not to arouse suspicion and gossip, which would have ruined the family. Darcy is ahead of the times by trying to get Lydia to leave Wickham when he first finds them, only arranging their marriage after she refuses to come to her senses and go home. (He also did manage to get his own sister away from Wickham.)
Part of the reason Mary has such a Misaimed Fandom is because of the range of things other characters get down on her for - everything from the truly obnoxious, like her moralizing lectures, to hogging the piano to...not being interested in balls. And this is used as grounds to say she's as bad as Lydia and Kitty. One has to consider, though, that balls were the primary way for young single people in the English countryside to meet and mingle (those in the city had other opportunities), and for girls like the Bennets who would be penniless upon their father's death if they didn't marry well, getting to know men at balls was crucial both for their own welfare and that of their family. So it was rather presumptuous of Mary not to at least make an effort to dance and socialize. (This is diminished in the 2005 film, where she genuinely makes an effort to practice music and sing at Bingley's ball and ends up humiliating herself.) Modern introverted readers who've been mocked for not being outgoing tend to see themselves in Mary, and forget how different their situations are.
While Mrs. Bennet was always intended to come off as silly, she comes off as significantly more so to modern readers than she did to readers in Austen's time, when marrying well was actually essential to a woman's future financial security. This is especially true with the Bennet sisters, who would lose everything upon their father's death (since the home is passing to Mr. Collins) if they have not yet married. To put it in perspective, a modern analogue would be the "helicopter parents" who obsess over their kids getting into a good university. Bride and Prejudice notably makes her obsessed with securing green cards so the daughters can go to America.
Mr. Bennet states that Lizzy is the kind of woman who would not be happy in marriage unless she "looked up to [her husband] as a superior", and Lizzy assures him that she does see Mr. Darcy that way. Although this one does depend on whether you think they mean that Darcy is socially or emotionally superior to Lizzie in standing or import (as in, Darcy is superior to Lizzie), or rather that they mean that he'd appear so when compared to the rest of the men around (as in, Darcy is superior to any other man Lizzie might be interested in).
In these days when Tall, Dark, and Snarky has become such a popular character type for male romantic leads, readers are likely to wonder just what Lizzie's problem with Darcy is, when at the time his wisecracks would just seem horribly rude. They also tend to overlook the fact that he insulted her personally; modern culture tends to position the Deadpan Snarker as a rather admirable character, but it's a different story when you're on the receiving end of his insults.
Those adaptations which don't just outright ignore the fact that Jane is supposed to be more beautiful than Lizzie tend to call on the values dissonance between Regency and modern standards of female beauty to play with it, by casting an actress who is beautiful in the classical sense favoured in the early nineteenth century (as typically found in Greco-Roman art) to play Jane while casting someone who is beautiful in a more modern sense to play Elizabeth.
Values Resonance: Jane Austen notably doesn't fall into the trap of Real Women Don't Wear Dresses that so many modern writers do when invoking The Glorious War of Sisterly Rivalry - where the 'smart' sister (or more importantly 'less feminine') is held up as the better of the two. Jane for example is the pretty sister, but her virtues are from her kindness and desire to see the good in everyone rather than her beauty. Lydia meanwhile embodies the negative qualities of the pretty sister - shallowness, being an Attention Whore, naivety amongst men. Mary likewise shows that the smart sister can have negative qualities too, as she's a Know-Nothing Know-It-All who's Not So Different from Lydia and Kitty. She's just as much an Attention Whore as them - but with her 'knowledge' rather than her beauty. Lizzie meanwhile has virtues that don't come from being less feminine than the other women around her - but from her awareness of the society they live in and her desire to challenge it.
Wangst: While her daughters do face ruin if they are unable to secure husbands, Mrs. Bennet's primary focus seems to be endless whining about how this will affect her.
The Woobie: Georgiana Darcy, once you learn her backstory. Her parents died, leaving her to be raised by her beloved older brother and cousin, and then, a former trusted family friend convinced her he was in love with her, and nearly got her to elope with him, all so he could get his hands on her dowry. She's also painfully shy. Luckily, Darcy rescued her, and she's presently very well-adjusted and happy, especially when Elizabeth becomes her sister-in-law.