Why would you buy such an expensive mobo? Why spend 100$ more on 470s compared to what you can get them for (270$).
That ram is a bad choice as well -- 1.65 volts for almost nothing. Save 50$ and get a G.skill eco kit at 1600 speed and 1.35 volts. PSU could easily be dropped to a Seasonic 750watt gold, which would be more than fine for 2 470s. Not to mention PSU efficiency is bell-curved, such that a 1200 watt PSU would see bad efficiencies compared to a lower wattage when used with such a low-demand system.
The motherboard has true 2 X 16 PCi slots. Where are you finding 470's for $270? The rock bottom cheapest that I see on Newegg (the recommended source) are sparkles for more than that. The EVGA's I reommended were overclocked, which graffex is unlikely to do himself. The RAM has CAS latency of 7, which is better than the eco. The overclocked 470 Nvidia cards have considerable power draw, which does not make this a low wattage system. If the bell curve holds true, then the power consumption would fall right in the middle of 1200 watt psu and therefore be most efficient. 1200 W is probably a little high, and should meet somewhere in the middle.