Dunno about the rest of the world, but from here it sure looks like Steam has folded - at least momentarily - under pressure. Had a feeling this might happen ;)
Muahaha - it's working now :)
Steam's working fine. There were a bunch of last-minute preloads going on, even though Valve upped the available bandwidth--so after HL2's launch, they increased the bandwidth even MORE, by as much as 50% on some content servers.
Valve has gone some serious power on their Steam servers.