My list from one of the most harcore gamers my age:
AMericas Army
Halo
Halo 2
Doom 3
Rainbow Six 3
Max Payne 2
Gta Vc
Half Life 2
Ninja Gaiden
GT4 prelude
GTA 2
Gunbound (very fun net game)
Cs (Decent but very over rated)
METAL GEAR SOLID: Solid Snake
METAL GEAR SOLID Speacial Missions
METAL GEAR SOLID 2: Sons of liberty
METAL GEAR SOLID: Substance (spent over a total of 2-3 days)
METAL GEAR SOLID: The Twin Snakes
METAL GEAR SOLID: Snake Eater
Mortal Kombat classic (like Trilogy, Kinda ruind em with Mk Da)
Sims 2
Battle Field 1942
Battle Field Vietnam
Battle Field 2 (looks good)
Fable
NFS Underground
NFS Underground 2
ESPN Football
mostly great games i play now