I agree with Will. 1978's "Superman" really was a huge achievement in the genre, as it made superhero movies acceptable for "name" actors and "event" movies, not just crap for the kiddies.
Granted, the first two Superman movies didn't do much to start a trend since there wouldn't be another real superhero hit until 1989. "Batman" had more of an impact on the genre in terms of direct influence, I think. "Superman" sowed the seeds - like I said, it made it okay for superhero movies to be seen as "A" films - but it didn't bring about a series of successful successors.
Heck, I can't even recall any other big-time comic book movies from the late 70s or early 80s. There must be some, but I can't think of them.
On the other hand, "Batman" set off a clear string of comic book successors. Other than Bats, only TMNT did well, though, which is why the genre faded again after a few years.
I think "X-Men" was the first salvo in the renewed, modern popularity of superhero movies, but "Spider-Man" was the biggest influence. Without the huge success of "Spider-Man", the genre might've faded again, but it made such insane money that it launched a whole lot movie comic book movies.
Unlike the 70s and 80s, enough of these succeeded to keep the genre popular - which is where it remains nine years after "Spidey".
So I think Sam Raimi deserves more credit for the current string of hit comic book movies, but without Donner, it's possible - probable? - none of the genre's later success ever would've happened...