HERO/Champions is my all time favorite system for roleplaying in the superhero genre. I love the fact that you can completely customize your character according to a point system, and it is pretty easy for the GM to keep individuals from getting out of control simply by enforcing the active point limits for powers and keeping a close eye on endurance cost.
I think that the system is best for supers, and I rarely use it for other genres, especially fantasy. That is, unless, you want a really high fantasy with powerful characters. The system also works great for kung fu games, since a lot of those get over the top. (I'm thinking "Kung Fu Hustle" type moves)
The fifth edition was well worth the price, and I plan on picking up the "ultimate" series soon, once I get through re-reading the basic rules.
[4 of 5 Stars!]