Your favorite PC exclusives

[Bodhesatva]

Since there seem to be a plethora of these threads for PS3 and 360 in particular, I thought I'd make my own for the PC. List yours! I'll restrict my list to only the last 3-4 years, just because it gets unwieldy to handle so many games if you go back too far. You are not obliged to follow that restriction. Remember, these are PC exclusives!

1) Company of Heroes
2) Portal
3) Team Fortress II
4) Civilization IV
5) Company of Heroes