The big ones: Doom 3 and Half-Life 2 (mainly because I enjoyed the originals so much)
Others:
AH2 - natch!
Pacific Fighters - natch!
Knights Over Europe (I think it is supposed to be released this year, but not sure - been looking for a good modernized WW1 sim)
SH3 looks good, but I think I will pass since it doesn't have a dynamic campaign (something like Aces of the Deep would be awesome). Also, I wish it was a USN PTO sim instead of u-boats, though I understand why you would choose them over the USN.
I am sure there will be a few others here and there that I may pick up. Oh, and the new Splinter Cell is quite fun.