If you're going to wait for Ivy Bridge release before building, why not go Z77 and get the comparable i5? You're using your own graphics and unless you're planning to use Intel SSD caching, there is no longer a reason to go Z68.
Also, you're spending a lot of money on air cooling, can get good performance for much less with either Hyper 212 EVO or a little less with Zalman 9900Max or Noctua NHD-14.
I'm not really in the know about graphics, but I do know that ASUS and EVGA are more popular brands, although I've seen a lot of Sapphire suggestions as well. If you look at the following NewEgg search for 680gtx, you'll see that all brands are sold out, so no brands seem to be standing out although EVGA has best rated.
Serial - you keep suggesting the PPC&Cooling 950W - with the new hardware there is no need for that much capacity even if SLI is an upgrade path. Get a more efficient 750W PSU. Edit - 850W to be safe.
http://www.pccasegear.com/index.php?main_page=index&cPa... <----- Z77 boards already for sale in Australia. In the past few years the Aussies have been getting the goodies a month ahead of the US and Canada including Sandy Bridge and the 1155 boards. The Aussies have already pulled some of the 1155 Cougar Point boards (H61/H67/P67/Z68) from their site. In fact a lot of those boards are no longer for sale on that site compared to last month.
System in IDLE = 155W
System Wattage with GPU in FULL Stress = 473W
Difference (GPU load) = 318W
Add average IDLE wattage ~20W
Subjective obtained GPU power consumption = ~ 338 Watts
Mind you that the system wattage is measured at the wall socket side and there are other variables like PSU power efficiency. So this is a calculated value, albeit a very good one.
GeForce GTX 680 SLI - On your average system the cards require you to have a 750 Watt power supply unit as minimum.