I put a brief link to this Marvel Super Heroes roleplaying game site up on this blog a while ago, but I'm giving it a bit more publicity as it's an amazing website. It's giving me loads of material on the site and the lively forum, and there's so much stuff on there I could run campaigns for months. Better yet, they've got every original TSR product on there as downloadable PDFs. That alone makes it worth the visit, but there's so much other stuff on there it's an absolute goldmine of information and material.
I've been toying with the idea of running a superheroes game for a while and I think I'll stick with Marvel Super Heroes. I've got the original books and I'm more than ready to get a decent game going.