Dorkly's website has a survey of the Greatest PC game of all time via a series of matchups as you go through and vote until you end up with your own list, while Dorkly keeps a place average (1-50) at the bottom. There's some glaring omissions on the voting list (why no Dawn of War?), but for the most part it's a pretty diverse spread.
UPDATE AS OF 2/25
The Average Top Ten
1. Half-Life 2
2. Skyrim (Tied with Half-life 2 at 73% though)
3. Portal 2
4. Portal
5. Diablo 2
6. Half-life
7. Knights of the Old Republic
8. Fallout 3
9. Starcraft
10. Morrowind
No real surprises here (except TIE fighter doesn't even crack the top 50, WTF?)
My own top 5 (doesn't show you your top 10)
1. MechWarrior 2
2. Curse of Monkey Island
3. Black and White
4. Max Payne
5. Diablo 2
UPDATE AS OF 2/25
The Average Top Ten
1. Half-Life 2
2. Skyrim (Tied with Half-life 2 at 73% though)
3. Portal 2
4. Portal
5. Diablo 2
6. Half-life
7. Knights of the Old Republic
8. Fallout 3
9. Starcraft
10. Morrowind
No real surprises here (except TIE fighter doesn't even crack the top 50, WTF?)
My own top 5 (doesn't show you your top 10)
1. MechWarrior 2
2. Curse of Monkey Island
3. Black and White
4. Max Payne
5. Diablo 2