This is the build http://pcpartpicker.com/user/ItsRemy/saved/#savedbuild_339774 its got a 650 power supply in it now, but I dont know if i should bump it up to a 750
Are you going to overclock or an add in another 7970 in the future or just buy a whole new graphics card like the 8970.
I know im only going to have the one card, but i think im too much a noob to start overclocking just yet, so probably not on this build.
If you are going with a single GPU and aren't doing much overclocking then 650w is fine. Especially with that Corsair unit as it has a nice solid single 12v rail with 50 amps on it.
I use a similar 650w in my build which is an overclocked hexacore and an overclocked GTX560Ti and it's been fine. I would guess you will be fine also.