PC gets Valve Anti-Cheat. Yay, Valve.
One hack in any game and your Steam account is banned forever.
Well, kind of. If they detect a hack installed while you are playing on a VAC secure server, they only ban you from games attached to it.
For example, this is the list of games I was banned from after Valve "detected" a hack I had running for windows in the bg:
Counter-Strike: Source (Game I was playing when the infraction took place.)
Counter-Strike: Source Beta
Team Fortress 2
Team Fortress 2 Beta
Half-Life: Source
Half-Life 2 (And all episodes + Lost Coast)
Half-Life 2: Deathmatch
Left 4 Dead 2
Left 4 Dead
Day of Defeat: Source
Source Dedicated Server
Spacewar
GoldenEye: Source (v4.1)
Dystopia
Pirates, Vikings, and Knights II
Portal
Portal: The First Slice
Eternal Silence
Synergy
So, I had to go and remove them all from my computer. Woohoo.