Released this year (for comparison purposes), in no particular order:
 
Orange Box
Bioshock
Medal of Honour: Airborne
Command and Conquer 3: Tiberium Wars
Colin Mcrae: DiRT
 
I haven't actually bought that many new games this year, so my options were a bit limited.  Here's my 5 favourite titles in terms of actual playing and enjoyment in 2007:
 
Quakeworld
Orange Box
Football Manager 2007
Freelancer
Test Drive Unlimited
 
I'm really looking forward to trying the likes of CoD4, STALKER, Crysis, Civ4 Complete, UT3 etc, but I doubt I will get time this year.  ATM my focus is on Bioshock.