Specifically, this week's highest grossing title on Valve's digital distribution service is Battlefield: Bad Company 2, which doesn't release until March. Mass Effect 2, which hits tomorrow, occupies the number two and three slots -- the Digital Deluxe and Standard editions, respectively. Modern Warfare 2 and Company of Heroes Complete Pack round out the top five. The latter came out last October and is certainly in some pretty good company.
Just missing the cut? BioShock 2, which is currently on sale for $5 off the $49.99 (virtual) sticker price.