What are your top 5 PC games of all time?

mine would be:
1. System Shock2
2. Starcraft (& Brood War)
3. Warcraft 2
4. Fallout
5. Deus Ex

Just missed the list: Dark Forces 2: Jedi Knight

1. Command and Conquer + Tiberian sun
2. Little Big Adventure 2
3. Dungeon Keeper 2
4. Theme Hospital
5. Knights and Merchants

1. World of Warcraft
2. Half-life
3. Diablo 2
4. Warcraft 3 RoC/tFT
5. Counter-strike

-edit-

Whoops, I'm an idiot and completely missed the PC part.

1. King's Quest VI
2. CS: Source
3. Sim City 2000
4. Starcraft
5. The Sims 2 

1) Counter Strike: Source
2) Doom
3) Half Life 2
4) Fable: The Lost Chapters
5) Zoo Tycoon with teh Dinosaur Digs expansion pack

Shame Project64 games can't be included....

1 . POP : Sot
2 . Warcraft 3 : Frozen Throne ( it was great ... Raign Of Chaos not so much )
3 . Quake 3 ( the best multiplayer FPS of all times )
4 . Quake 2 ( the first real 3D game )
5 . Gothic

Damn totally forgot about half-life :S

Dune 2
Half Life
Civilization (the original)
Railroad Tycoon (the original)
Space Quest

1. Starcraft
2.Wolfenstein Enemy Territory
3.Civillization 2
4.Warcraft 3
5.Heroes 3 might and magic

Genius Games and multiplayer in Starcraft and Wolfenstein made me a pro

1- Monkey Island 2

2- Grim Fandango

3- Planescape Torment

4- Day of the Tentacles 

5- Ultima 7