Saw over at Console ActionTrip a list of potential Xbox 360 launch titles. If this turns out to be true, the only title I care about is Call of Duty 2, but not enough to want to go buy an Xbox 360 for it alone. I'm surprised Quake 4 isn't on the list.
Generally, I have a feeling it will be best to wait until the next wave of titles in late spring early summer of '06. With any luck Halo 3 will be coming out around then.