I've managed to keep Steam under control, probably because I prefer boxed copies. I just go for the special offers. Got stuff like the Oddworld games, Secret of Monkey Island, Portal, a number of indie games, etc. Only "big" titles are Empire TW (didn't have a choice there) and Dragon Age because I prefered the Digital Dekuxe over boxed.
It's indeed these latest games that eat away at available space like there's no tomorrow; 15GB just for Dragon Age.