In no particular order
Sins of a Solar Empire
Crysis
Bioshock
The Orange Box
Company of Heroes
World in Conflict
WoW: The Burning Crusade
1701 A.D.
The Witcher
Medieval II: Total War
I don't know if I'd really call it my top ten list, but it is ten good games that came to mind. Oh, and if Civ IV counts, throw that in the list too.