Here is the screaming example of what Microsoft meant about gaming on the 3 screens: RC-AirSim is a game that can be found on the PC, the XBOX 360 and in Windows Phone 7.
The game is pretty much the same on all 3 screens, and I dare saying that on Windows Phone 7 it runs better than on my PC
Also the XBOX experience is very good, and you can notice some effects enhancements like some particles coming from the plane.
So far I’ve purchased the XBOX version, and its only too bad you have to pay for a license for each platform and that you cant just buy one license to have the game for all three platforms.
In the future, one might expect to play your favorite game anywhere you are, and hopefully you will only have purchase it once.