It's generic shite. Superman in general is boring as hell, the guy can't be hurt in any way - what's the point in a dramatic CGI battle sequence if you know that he won't stay down regardless of how many trains planes and automobiles they smash on his head.?
Superman is probably my least favorite of the "big" superheroes, not really for the reason you stated but just because I don't find most of the storylines to be as interesting as some of the others (comics or movies). I did have a crush on Lex Luthor as a kid though, that bald fucker.
My ranking is X-Men, Batman, Spiderman (minus "emo Spiderman" which is probably the worst thing in the world), then Superman.