Gaming is superior on the PC, but since I'm console minion, I gotta say:
The PS3 has free online service. I'm sure thats what brings a lot of people to it, except it lacks a lot of online features that the xbox 360. For instance, cross-game group chats. The xbox 360 is more feature-rich, and made for gamers who will play online with their internet-buddies and irl-friends in large competition. The PS3 is more laid back, not that much competition; good for people who are playing for fun, not to be top dog. From what I've read, Sony now offers PS+, which has similar features to the Xbox 360's.
I don't suggest getting an xbox 360 JUST for Kinect. Right now, Kinect seems like a failure...