CoH/CoV was an awesome game, and I miss it terribly. I've also done some Champions Online and DC Online, which each have things to recommend them, but I guess you never get over your first (superhero MMO, that is!).
The differences between superheroes in comics and superheroes in games is interesting, to me. In a game, everyone is designed to balance with each other and sort of inter-depend during a fight, instead of the comic book standard where character 1 might just be better at *everything* than character 2.
Applying CoH terms to comic book heroes, everybody seems to be a blaster, tank/scrapper or tank/scrapper/blaster hybrid, with surprisingly few 'controllers' or 'defenders' (or masterminds!). It's fun when designing characters to find niches that aren't as well explored, where there's lots of 'design space' left open to play with.