I could probably go for quite a while on just Valve titles, actually.
Really... Valve doesn't have that many actual titles last I checked.
According to Wikipedia, they have developed:
Half-Life (PlayStation 2, Windows, Linux) with 4 expansions (Opposing Force, Blue Shift, Deathmatch Source, Decay)
Half-Life 2 (Windows, OS X, Xbox, Xbox 360, PlayStation 3)
Half-Life 2: Episode One (Windows, OS X, Xbox 360, PlayStation 3)
Half-Life 2: Episode Two (Windows, OS X, Xbox 360, PlayStation 3)
Counter-Strike (Xbox, Windows, Linux)
Counter-Strike: Condition Zero (Xbox, Windows)
Counter-Strike: Source (Windows, OS X)
Counter-Strike: Global Offensive (Xbox Live Arcade, PlayStation Network, Windows, OS X)
Team Fortress Classic (Windows)
Team Fortress 2 (Xbox 360, PlayStation 3, Windows, OS X, Linux)
Day of Defeat (Windows)
Day of Defeat: Source (Windows, OS X)
Portal (Xbox 360, PlayStation 3, Windows, OS X)
Portal 2 (Xbox 360, PlayStation 3, Windows, OS X)
Left 4 Dead (Xbox 360, Windows, OS X)
Left 4 Dead 2 (Xbox 360, Windows, OS X)
Alien Swarm (Windows)