Well I agree that I really like STEAM as of the last 5 years.  But when I was a big Counter-strike whore (1.5 and previous versions) i was really reluctant to get 1.6 on STEAM.  And it was a valid reason, because servers could no longer be in charge of version control.  Every week STEAM updated CS 1.6 and changed the game mechanics.  Previously in Counter-strike every "update" had to come in a new version, so servers and gamers could decide if they wanted to play on the new version or not.  I remember playing 1.3 for a long time after 1.5 came out (after a brief 1.4 release).  I still think CS 1.5 is the best version that was ever made.  Or possibly the very first versions of 1.6.  Source is a bastardization of CS, just like every "source" version of an original HL game.  DOD:S, TF2, etc, they all suck (as far as gameplay is concerned) compared to their original Half-life mod.