Skateboarding on 360
It was a tough choice between Skate3 or Tony Hawks RIDE. I had only briefly played Skate1, and I grabbed the Skate2 demo, then the Skate3 demo which made my decision.
This game is a lot of fun although if you are not into skating it may get boring quickly. Playing on Live with randoms was OK and one guy even helped me out with tips on how to perform some of the challenges.
I am yet to play with the skatepark editor, but I always enjoy any sort of level editing in games.
A must buy if you like skateboarding and definately consider Skate3 if you are looking for something new, challenging and different, with a nice amount of community created content.