These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
Ensemble Darkhorse: Finch has a lot of fans especially among readers that aren't entirely convinced of V's virtue.
Genius Bonus: In the film, when V drops in on Creedy's residence, their conversation is masked by Beethoven's 5th Symphony — the viewers only hear the first bar but, when interpreted as Morse Code, it's the letter V (...-).
Memetic Mutation: Like you wouldn't believe. From a single Epic Fail Guy comic to the face of worldwide protests. Today, V is the face of Anonymous. Along with the infamous "V" speech. Evidently, Moore is actually quite proud of this fact, but is a little annoyed that it was sparked not so much by his comic as by "the rubbish movie".
Misaimed Fandom: Meta-example, as it did this to Guy Fawkes. It's true that Fawkes entered Parliament with honest intentions, but few actually know what those intentions were. He wasn't trying to take down an authoritarian government, but instill a different one (indeed, since the Catholic church strongly believed in the divine right of kings, Guy Fawkes's co-conspirators would most likely have abolished the power parliament had claimed from the crown). He wanted England to move from the Church of England, which was oppressing to the Catholic Church, back to the Catholic Church (which would then have oppressed the Church of England).
The movie has spread the misconception that November 5th, Guy Fawkes Day, honors Guy Fawkes, the plucky rebel, instead of celebrating the fact that England narrowly averted a terrorist attack on the capital. It's like thinking September 11th honors Osama Bin Laden.
V. Though the film does play the hero angle a bit more straightforward than the comic book, it's still made very clear in the film that V is a terrorist who took his likings of Fawkes' philosophy too far.
Rooting for the Empire: Happens to V himself, thanks to being portrayed as a saint in comparison to the Norsefire government.
Unfortunate Implications: They established that having sex with Evey is pedophilia, but there is also the fact that V seems to want her as well.
It's also okay to torture someone for months on end, as long as you feel bad about it. V receives no direct comeuppance for this, unlike he did in the book.
They Wasted A Perfectly Good Line Art: It was originally released in black and white, and then recolored by a different person. With watercolors. In quasi-impressionistic colors. Without paying attention to the lines.