Steam Games: CS:S, Portal, Half Life 2, 2-1, 2-2, Team fortress,...

Well i guess this will be our Valve/Steam Games topic...
So here you can talk about:
Counter strike (1.6, Condition Zero, Source)
Half Life 2, HL2 Episode 1, HL 2 Episode 2
Half Life 2: Deathmatch
Portal
Team Fortress 1 & 2
And if you know more games that are made by them... Or if you know a good Mod for any of these games just post it !

Grtz!

ShinaiKara.