Spider-Man: I think the fact that Spider-Man comes from a maybe lower-middle class background and always seems to be having cash problems would make him a liberal Democrat
Superman: Grew up in the heartland and seems to be a law and order type so I think he would lean to the GOP
Batman: Also a law and order type but his insistence to never use a gun or kill criminals may make him a Democrat or at least a moderate republican
The Green Arrow: As us superhero fans know Ollie is on the left. In real life he would have a blog and maybe write for the Nation
The X-Men: Well the Republicans would hate Mutants so the X-Men would be liberals. However I could see some people on the far-left thinking that The X-Men never really do anything for mutant rights and just fight other Mutants. I could see Alexander Cockburn writing negative things about them.
Lets see If we can think of more.