It is indeed for a single graphics card. So yes it probably is over kill. But right now I have a 500 watt psu. Seems silly to buy a new one because the 500 watt is not enough and only upgrade to 550.
Plus I like the modular cable design and the reviews I read. The fact that it was $5 dollars cheaper shipped then the cosair 550 did not hurt either.
It is un likly i will add a second card. I'm thinking a single 470 will handle my needs. If it turns out not ... I'll probably kick myself for not getting the corsair 850 I almost bought.http://www.tigerdirect.com/applications/SearchTools/item-details.asp?EdpNo=4352342&sku=C13-2508
for the full system see this posthttp://www.tomshardware.com/forum/283304-28-squeak-watts