As proven in past posts, STEAM is a big pile of URINE!
HL2, while certainly better than Doom3 by anyones guess, is not the holy grail of gaming, but rather another set of cleveryly scripted interactions based firmly in FPS conventions.
Getting permission from Mommy Valve via an internet connection to play a single player game is a step backward in customer relations. First game companies try to force their users to act like dogs and fetch their CDs, now they try to force us to call Mommy when we want to play.
Eat your own URINE valve!