What are your top ten favorite first-person shooters?

[canch]

But these are not in order of my best, to hard to decide.

1. Counter Strike (PC)
2. Left 4 dead (PC)
3. Half-life (PC)
4. Delta Force (PC)
5. Golden Eye (N64)
6. Aliens Trilogy (PS1)
7. Team Fortress 2 (PC)
8. Quake 3 Arena (PC)
9. Unreal Tourament (PC)
10. Battlefield 1942 (PC)