I have heard that the reason that the XBox live games cannot be played with friends on Windows machines is that when MS tried it out, the keyboard-based players were so dominant that Microsoft decided not to allow the capability. Specifically, I've heard this about FPS games.
This is repeated in many places, for example on this forum:
Definitely PC on the FPS front. Unless you plug in a mouse to the console. Mouse and WSAD are -much- better than console autoaim and all that, to be honest. Not to mention that due to more control, the PC FPS games tend to be more fast-paced than console ones, where part of the difficulty of the game actually lies in the controller.
So have Windows-based FPS players been proven to be generally superior to console FPS players, thus making this story plausible?