You may laugh at me, if not at least I'll laugh at myself.
NFSMW
Halo
Age of Empires 2 (with conquerors expansion)
I never play them much anymore though, not a big gamer. Flight sim seems neat, don't know if my desktop would handle even the older version though. My brother will sit on the PC playing games all day if you let him, has also has a bigger game collection.
BF2 (won't work on his PC until he upgrades)
Oblivion (same deal as above)
COD
COD2
Half Life 2
Battlefront 2
Battle for Middle Earth
CS:S
That's all I remember.