As a heavy Media Center user, I'm hopeful we'll see this optimized for Media Center sooner rather later...not so much for hand gestures but voice control.  Amulet Devices does a really nice job.  I just could do without Amulet replicating Media Center apps and indexing media into its own database.  The missing ingredient that XBox has is "profile" recognition.  With Amulet, you have to say "my name is soandso" for it switch to the right Windows Speech Profile.