Well, the PSU is major overkill. Even a quality 600-650W power supply could handle this entire system. AMD recommends a 500W power supply to power a system with a single 6950 in it, so that means they would recommend a 600-650W for two (but they're referring to peak-rated units, and I only shop for continuous-rated units):
Here are 5 that I recommend (sorted by price):
The 650W SeaSonic X-Series is the best 650W on the market and it is fully modular. However, 650W XFX "XXX" Edition is right on par with Corsair's HX650 and it is just as modular as it (not fully, but still very modular). The 650W TruePower New is right on par too, but it is only partially modular.
The 620W SeaSonic M12II is modular too and is another really good choice.
If it were up to me, and if looks were not important, then the XFX "XXX" Edition wins. However, if I were doing very extreme overclocking (like using extreme, sub-zero cooling), then I'd choose the SeaSonic X-Series due to its extreme quality.
Although, for maximum value, practicality and looks, I think the winners are the 650W TruePower New, 620W SeaSonic M12II, and even the HX650.