PS3 - Only a couple hours per week right now, Madden 11 is the only thing I play on it. GT5 will change that.
360 - As much as I can! Could be as high as 20 hours or as low as 10 if I'm too busy. With New Vegas tomorrow and Black Ops very soon my 360 will be running hot and RRoD is a serious fear of mine. (I'm not joking or trolling, I'm going to play 360 so much it'll probably RRoD)
PC - For surfing the net about 1,000,000 per week; for gaming 0 hours per week







