Spider-Man is the best superhero movie of the past 20 years.
It's closest relative in the success of translating both the immense scale and intimate characterizations of the character is 1978's Superman. When Superman was released, Christopher Reeve was an unknown who took that blank slate and brought Superman to life, his Clark Kent was a bumbling and stumbling fool while Superman was heroic and majestic. I thought Tobey Maguire was a good choice to play Spider-Man but worried that his fame may dominate the role - so it would be "Tobey Maguire as Spider-Man". Well, file that away in the cabinet of bad ideas, because Tobey Maguire is the living embodiment of Peter Parker and Spider-Man. Instantly you sympathize with the character, the lowly everygeek who gets pushed around at school and dares not approach the girl he's loved since he was six, filled out beautifully by Kirsten Dunst.
X-Men was a good comic-to-screen execution but had the unfortunate need to explain several characters' origins in a short amount of time, Spider-Man takes the advantage of a solitary origin and allows us to see the character evolve with time - stunningly faithful to the source material but moving at a good on-screen clip. When Peter is bitten by the spider and receives his powers, you jump with him roof to roof, laugh as he tries out his new abilities and marvel as his motions loosen up and become like the human spider who's existed in our minds and in two dimensions for these many years. Instead of dark and brooding, we get a hero who takes tragedy and becomes heroic and a symbol to the people he helps. The credo of "With great power comes great responsibility" is translated by Maguire into the "Friendy neighborhood Spider-Man" who makes the skyscrapers of New York his home.
The Big Apple should get some on-screen credit as well, Spider-Man is able to simultaneously swing above the people but weave his web from building to building - never skipping a beat as it becomes second nature to wind his way through this world unto itself.
Willem Dafoe does a good job as industrialist Norman Osborn who makes the transition to the maniacal Green Goblin. The scenes where he struggles with his madness are both funny and sad, while the explanations for his appearance are actually made more logical within the context of the film than in the comics - usually the opposite. My only complaint is that he is a little too much of a wisecracker than menancing villain, but his actions in the films final third make up for it.