I will make a little game list. Just post good games, list will be edit every day. (@ nokill, make it sticky :O)

First Person Shooter
Aliens Versus Predator 2
Battlefield 1942 + Secret Weapons of WW2 + Road to Rome
Battlefield 2
Battlefield Vietnam
Call of Duty 1 + United Offensive
Call of Duty 2
Call of Duty 4
Counter Strike 1.6
Counter Strike Condition Zero
Counter Strike Source
Crysis
Day of Defeat (Source)
Doom (all) / Hexen
Duke Nukem 3D
Half Life + Blue Shift + Opossing Force
Half Life 2 + Episode 1 and 2
Halo
Halo 2
Painkiller + Battle out of Hell + Overdose
Quake (all)
Red Orchestra
Return to Castle Wolfenstein
Star Wars - Republic Commando
Team Fortress Classic & 2
Tom Clancy's Rainbow Six Vegas
Tribes: Vengeance
Unreal Tournament (all)
XIII










Real Time Strategy
Battle for Middle-Earth
Battle for Middle-Earth 2 + Rise of the Witch King
Black & White
C&C (JUST ALL)
Company of Heroes + Opossing Fronts
Faces of War
Rome: Total War
StarCraft & Brood War
Stronghold
Stronghold Crusader (extreme :O )
Stronghold 2 + Legends
Warhammer 40.000 - Dawn of War + Winter Assault + Dark Crusade + Soulstorm
Warcraft 3 + The Frozen Throne
World In Conflict







Role Play Games

Baldur's Gate
Baldur's Gate II: Shadows of Amn
Diablo + Hellfire
Diablo 2 + Lord of Destruction
Fable: The Lost Chapters
Gothic
Gothic 2
Gothic 3
Icewind Dale
Neverwinter Nights
Neverwinter Nights 2
The Elder Scrolls 3 - Morrorwind
The Elder Scrolls 4 - Oblivion + Shivering Isles + Knights of the Nine



Massively Multiplayer Online Role-Playing Game
9 Dragons
Age Of Conan
Anarchy Online
City of Heroes
City of Villains
Dark Age of Camelot & Shrouded Isles
Everquest 1 & 2
Final Fantasy XI
Guild Wars
Silkroad
The Lord of the Rings Online: Shadows of Angmar
World of Warcraft & Burning Crusade



Other
Crashday
Flatout 2
Scarface
GTA (JUST ALL)
Trackmania Nations Forever
Worms (JUST ALL)

You missed a few...

rpg
Neverwinter Nights
Neverwinter Nights 2
Baldur's Gate
Baldur's Gate II: Shadows of Amn
Fable: The Lost Chapters
Icewind Dale


Rts
StarCraft & Brood War
World In Conflict
Black & White
Rome: Total War


Fps
Unreal Tournament (all)
Quake (all)
Team Fortress Classic & 2
Duke Nukem 3D
Tribes: Vengeance
Aliens Versus Predator 2
Doom (all) / Hexen
Half Life: Oposing Force
Half Life: Blue Shift

MMO's
Age Of Conan
World of Warcraft & Burning Crusade
Guild Wars
Everquest 1 & 2
Dark Age of Camelot & Shrouded Isles
Anarchy Online
City of Heroes
City of Villains
The Lord of the Rings Online: Shadows of Angmar
Final Fantasy XI

and where do u get off not calling Diablo + Hellfire Diablo 2 + Lord of Destruction and Flatout 2 not rpg's?? they are all amazing rpg's that set the standard for many other games to follow they go under the specific genre of Action RPG

So here are some more you forgot:

Gothic (all, very famous in Germany)
Serious Sam (all)

1. Diablo is a Hack 'n' Slay
2. i mean the Derby Game Flatout 2, not Fallout 2

but yes, i can write diablo as rpg

but gothic isnt a good game sad.... gothic sucks balls.

talk about a glitch/bug fest

1 was kinda shit, 2 was quite ok and 3 suckz great monkey bawlz tbh.

I always had more fun with Day of Defeat 1.3 than with Source.

yep, me too

So then why didn't you list it?

i did....

Day of Defeat (Source).... Source is an alternative :O
and if you say day of defeat, you mean 1.3, cause you cant have an other patch version cause of steam

I said Day of Defeat 1.3...

virus too ...

ermmm gothic 2 rules tbh [=

its a good game but gothic 2 with oblivion 4 gfx would look good but it will comes soon=> gothic 3