Here are my top 10 first person shooters.

Half-Life
Half-Life 2
Counter-Strike
Call of Duty 4
Battlefield 2
Doom 3
Tom Clancy’s Rainbow Six
Far Cry
Resistance Fall of Man
FEAR

Looks like its Valve’s Half Life series are my favourite. half-Life has the most amazing story in a first person shooter along with Half-Life 2, i could still go back and play them games over.
Counter-Strike, [...]