I'm not gonna lie, I've got a huge super-thing going on. In fact, the way I understand a new book or system, is by trying to make Batman or Wolverine in it, as sort of a test. Once I figure that out, then I'm ready to use the system for real.
I also really love crossing and mixing genres. Putting Jedi in D&D games, putting Superman or Green Lantern in Star Wars games, playing like 'slasher hunters' in standard superhero games, etc. I'll admit that few others seem to share this morbid interest, but I don't think I'll ever stop.