I agree with everything Tim said about "X-Men," especially the spot on casting of Patrick Stewart and Hugh Jackman. However, one thing I wanted to discuss is how comic book movies were in a slump until "X-Men" restarted the genre.
"Batman & Robin" had been a massive failure and not only ruined the "Batman" franchise, it scared studios away from sinking money into big properties. Ridiculous films like "Barb Wire," "Steel" and "Tank Girl" were the only comic book movies being made for a while.
But when "X-Men" came out and the studio cast real actors like Stewart and Ian McKellan, and were faithful to the characters, it proved that fans and critics would support the genre if it was well done.
The success of "X-Men" brought the "Spider-Man" franchise, "Batman Begins" and "The Avengers" series of films. It also led to "X2: X-Men United," which is one of the best comic book movies ever made.