Just bought World of Goo :)
YEAY!

I really love Steam sales. They make the games cheap enough for me to get them.

The PC forum on VGC is really struggling when half of the threads are promoting deals on Steam.

Purchased. $20 was a bit steep for me, but I would have gotten it even at $10. $5 seems like a steal.

I'm now playing chapter 4, and I must say, the demo fooled me. I admit that even after amazing reviews I didn't think there was much they could do with goo balls, and playing the first chapter in the demo didn't help much. but the way the game progresses and the new stuff it introduces are just fantastic. $5 is extremely cheap for this game, I'd say that $20 is fair if the WiiWare version wasn't cheaper, because it is fair :P