Steam is fucking me too. I can't play L4D2. It says "validating cache files", then says "steam servers busy" and won't launch. Tried deleting some cache files but no go. I'm downloading a new install into a new folder and I'll see if that works (deleting local game content had no effect as I was not able to re-download the game).
Fuck these sales. Command and Conquer games for $4 each. There goes $20. I don't even plan on playing them any time soon. But I do love me some CnC and haven't kept up recently (before you say 4 is shit, remember that it's $4).
Mass Effect 1 + 2 for $20.