Hmm... I'm not big on Justice League-style RP, but if it was a smaller team, that could work out. Or we could have just three heroes and each have a turn at making a villain for us to face down. That is, of course, assuming we want nice and shiny heroes. If we want something darker, I always enjoy a good vigilante-style RP, though, admittedly, I'd probably play the person trying to bring the vigilante to justice if we did that.