[quote name='evanft']Wow, I thought the reaction was gonna be bad. How much was changed from the book?[/QUOTE]
*MINOR SPOILERS*
They added some material and the cut some material, but the changes were really all for the best. For example, the High Chancelor in the movie doesn't have his computer fetish from the comic, and Detective Finch makes some leaps in logic at points, mostly because he doesn't have the extended acid trip at Larkhill, so they needed alternate ways to convey that information. Evey also shacks up with a different character when she leaves V, I would guess because his death in the book is too unrelated to the main story. They also added a domestic 9/11-style terrorist attack, to update the political climate from 1981's "near-miss nuclear exchange between the US and USSR," so while I'm sure some politically sensitive types will bitch about such things, it was a smart move. How things work out for V in the end also unfolds a little differently, although the major notes are the same. That's also tied to the "computer love" plot being dropped, in a roundabout way. All in all, exceptionally faithful to the book in detail, and in spirit when that wasn't possible.