Viggo was rumoured (or at least on fans' wishlists) for Tony Stark at one time and also is supposed to have turned down the role Liam Neeson played in Batman Begins.
He really doesn't seem the type to do them silly comic book movies.
I didn't say that.
He did after all appear in A History of Violence, which is based on a graphic novel, but it's not a superhero movie. But when Batman Begins was being cast, I remember the story was that he and Daniel Day-Lewis had turned down a role, which Neeson then accepted.
I kinda get the impression that since LOTR, he has wanted to concentrate on indie and non-mainstream movies for the most part. But I'd love for him to prove me wrong.