PC and consoles have one major difference: proper digital delivery.
For PC you have these fine options:
*GOG – good old games to download in digital format for small price. PC rocks.
*Tons of more places to get indie and AAA games: Direct2Drive, Steam, Gamersgate… and more. I don’t need physical copies for PC, I can buy them in digital format.
The point is… if for example I want pretty much any game (that was published to) PC, I can get it. Consoles don’t have proper digital delivery. Yes, PS3 offers some demos via playstation network and sells some minis and classics and whatnot, but their catalogue is lacking badly. Xbox live is doing a better job in live area but if I understood correctly, you cannot get for example Alan Wake as a digital download. You (most likely) need to get a physical copy. Same with Wii and others.