Just so everyone knows, the Steam Auth servers are back up and working. The message from the http://www.steampowered.com
(well, their RSS feed) is:
We have resolved the issues that caused some to experience delays with Half-Life 2 authentication earlier today. We appreciate your patience and hope everyone enjoys the game.
Personally, I've had no trouble with it, but then I could well have been asleep during the crucial period of downtime. Also, as I unlocked HL2 approximately 10 minutes after if became available, I might have got on before things got really overwhelmed
Yes, HL2 is amazing.
BTW, Alex, best of luck with SF2! One of these days, I'll quit my current job and be able to commit some time to working on a mod of some sort.