Battlefield 2142 looks good. It was released on the 18th. Unreal Tournament 2007 is being released on 10th November and will be a good game. Other than that Half Life 2/Counter Strike: Source, Oblivion and F.E.A.R are all good games.
Everybody seems to like Half Life 2. I have the game on Steam and to be perfectly honest, hate it! It's probably just me though, because I never like to play single player games - multiplayer FTW!