1. Spider-Man - Very solid movie, super-hero or not, no major problems. Given Marvel's history of movies, I'd have never thought they could put out something this good. It also has a remarkably broad-based appeal.
2. The Crow - Another very solid movie. Tragic character, and a tragic story behind the movie. Most revenge plots bore me to tears, but this one was interesting. Awesome soundtrack.
3. Batman: Mask of the Phantasm - The animated Batman is a far better representation of Batman than any of the live movies. Like the other movies I ranked highly, this movie had a romantic plotline that was actually interesting; few super-hero movies pull this off.
4. Superman - You can't argue with the classics. Even with all the later incarnations of Superman in the movies and TV, this version had a certain charm that we don't see in the others.
5. Superman II - Not many sequels have managed to recreate the same elements that made the original so good. I really liked this one, too, but it's a bit harder to compare these older ones, which carry a lot of nostalgia, to more recent ones. I haven't watched it completely through in years.
6. X-Men - Really good, for a more-or-less mindless action/adventure movie. Surprisingly faithful to the characters (which seem to have been floudering for years in the comics, IMHO), although I wish they had gone with something more like the current X-uniforms, if they weren't going to use costumes. Black leather is not very distinctive, these days.
7. Blade - Also a good action movie. Blade doesn't really come off as a particularly interesting character, though. He's pretty much just a one-dimensional bad-ass (in other words, boring). But the action scenes are great, and it's a really interesting take on vampires (the club scene is great).
8. Batman - Batman's one of my favorite super-heroes, so perhaps I'm a bit hard on this movie. It did a lot of things right, but it definitely had problems. Some of these things were made better in the later bat-films. For example, Batman fights like a real martial artist, not like a stiff zombie. But the later movies just had so many bad elements that they've kind of ruined the whole franchise.
9. Daredevil - This movie does a lot of things right, and maybe with time, I'll rank it higher. I don't think there was enough character development for Daredevil, though.
10. Darkman - Pretty good Sam Raimi movie. It worked well as a movie, but the character doesn't have the same appeal as the more classic tragic super-heroes that this movie is loosely based on. I can't stand the last Darkman movie, where he suddenly has a British accent (I think, I forget exactly what the accent was).
Honorable Mention: The Shadow - I'm not old enough to have grown up on the radio show, but it seems to have been very faithful to the character. I liked it.