Let's see....
The Suffering: Ties That Bind - good sequel, with better graphics and a look into Torque's past...
Jade Empire - Great RPG, but for somereason, not drawing me in as much as I though it would (probably b/c of Oblivion)
F.E.A.R. - Really good, my comp can handle it on medium-high settings (soft shadows still crippling)
SSX3 - Had this on GC, and felt that since I have the 'Box now, I should switch over, but still no custom soundtracks :(
Pikmin 2 - Never played the first, because of the time-limit ordeal, but this one clearly beats it out.
Burnout Revenge - not necessarily better than Burnout 3, but the new traffic checking really gives you a sense of completeness when battling against the brutal rival cars... no drivers in their cars this time...
Mercenaries (still haven't beaten it) - still good, but the final mission, which I've tried many, many times already, is very, very tough... be warned.