PS3 for the most part. It has got the most exclusives, although I do occasionally enjoy a bit of Mass Effect 1 and 2 on my Xbox 360. I use my computer mainly for editorial purposes, for my e-mail, Windows Live Messenger, editing and more general PC tasks.
And don't get me started on the Wii: I may have about 50 to 60 games on both the PS3 and Xbox 360 alone (that would make for a staggering amount of 120 different games, ouch), but the Wii has failed in my opinion. It's just sitting there, collecting dust, and I've only got about 9 games for it.