I despise EA.
Anyway, I also highly suggust half-life2, diablo1, 2, 2's expansion, starcraft and it's expansion.. just about any game from blizzard is worth playing.. cept World of Warcraft.. not worth the monthly fee.
Quake IV is kick ass,
Prey is decent,
Fable kicks ass,
FarCry is good,
Unreal Tournament 2004 kicks MAJOR ass,
and uh.. thats all I can think of right now.. cept counter-strike.. but I usually only play that when I have friends who want to play with me or I dont' have anymore single player games to play.
However.. if you want old school.. you can always go play Doom2 on the zdoom source port! (http://www.zdoom.org/
or for multiplayer there is always zdaemon (http://www.zdaemon.org/
has a vast library of custom levels for doom.. ahhh how I continue to love this game despite it's age.. all thanks to id releasing the source code.