Pretty much anything previous to '09, and most modern games as well. Only Crysis 2, 3; Metro 2033, the witcher, maybe bf3 won't run on ultra. Actually a few more modern games need high settings, but is ultra that important to you? They will run on high (which is still good, trust me)
Update: Farcry 3, and assasin's creed probably no. I'm not sure how demanding skyrim is with that mod.