It can't tell you, because you'd need a nuclear reactor or two to power one of those things up, which is easily over 9000W.
Jokes aside, nVidia recommends a 600W minimum power supply for a system with a GTX 480 in it. Normally, ATi/nVidia overestimate how much power you need for a system, but this time, I don't think that 600W is too much of an overestimation, so go for a 600W to 700W PSU, Corsair or SeaSonic preferably - for a GPU like this, I'd definitely get a high quality power supply.
Just a small recommendation, but why get the Intel Core™ i7 950 3.06GHz, if you could get the i7 960 3.2GHz for the exact same price, or, why not get a i7 930 and overclock it to those speeds? I'm just assuming you haven't bought these parts yet, so you really should get either the i7 930 or i7 960.
OOOOOh man I never now about i7 960 ...I already bought the i7 950...
I'm very sad now ... is it toomuch different in performance (please say no