I think the next Xbox will have to move into full 3D. 3D with what they are going to do with Kinect would be awesome! But, the standards aren't really there yet, HDMI 1.4 is a good step, but seems insufficient now that I have been spoiled by some really good tech. Plus, monitors are already moving beyond 1080P and the new consoles will need even more amazing graphic power.
I know I'm kinda spoiled, but I don’t enjoy going from my 120Hz monitor, to 60 frames per second per eye. It shows up and make artifacts and just isn't quite good enough for me yet.
Now, soon, hopefully they will be getting better at making 3D without glasses. That would really be a boon - 3D TV with no glasses. :D