You can literally buy brand new GPU by just playing PC games: http://raptr.com/store?category=hardware
I did win few AMD sweetakes myself. Also combines console trophys/achievements and shows if friend plays other than steam game or console game.
Xfire I mainly use for FPS and clock overlay lol
Well shoot, I didn't know about that aspect of it. I -might- just have to look into it then. Granted, I don't have much time for gaming these days and I'm still pretty happy with my gpu (Geforce GTX 560Ti), but that's still an interesting prospect to be able to win/buy stuff just by playing games then.