As far as the PS3 and Wii go, we know the following from watching Sony and Nintendo financials:
(1) The PS3 is losing a lot of money per unit sold. Almost certainly over $100. Sony has been posting HUGE losses despite the PS2 making money and game licensing making money.
(2) The Wii is making quite a bit of money per unit sold. Probably over $50. Nintento has been posting HUGE profits even considering DS profits.