The first Spider-Man was pretty close. The only major complaint that I would have with that first one is with MJ as the next door neighbor.
Magneto in the X-trilogy was pretty solid. Only criticism is that there was no explanation behind the total psychotic twist that we saw from him in the third film. Usually with Magneto in the comics, there is something behind his more psychotic turns.
As much as I love all three Spider-Man movies, including the vastly underrated Spider-Man 3, Tobey Maguire was badly miscast as Peter Parker. Ironically, Topher Grace would have been a much better choice, as he's just as skinny as one would expect Peter Parker to be, and we already know he's a master of the deadpan humor that is Spidey's trademark. Maguire would have been much better as the grim, humorless Eddie Brock that's everything Peter Parker could have been if he'd taken a darker path.
Kirsten Dunst was also badly miscast as Mary Jane. Someone like Anne Hathaway or Scarlett Johanssen, someone who's a drop-dead hottie-which Dunst most certainly is *not*, especially by the time the second and third films rolled around-would have been far better for the role. Not to mention Dunst plays her like a whiny, nagging shrew-exactly why we're supposed to sympathize with her is entirely beyond me.
That said, I still feel all three spider-films did a wonderful job in replicating a lot of the major themes of the comics, namely power, responsibility, and redemption. Just as I find the Spider-Man comics to be among the only things Marvel prints that are worth reading these days (aside from Spider-Girl, and possibly other things that Bendis and Millar haven't taken a creative dump on like they did with the Avengers and the Marvel Universe in general), the Spider-Man films are and remain my favorite Marvel films.