Would go cheaper considering this is an AMD build, at your pricepoint an Intel build would be a bit better.
At least from what I see. Critiques so far, The Hyper 212 Evo will be enough, you're not overclocking GHZ OCs which push the FXs or any chip over the typical stock voltage give or take. Which means heat will not be THAT MUCH higher, it'll be enough that the 212 Evo can handle, it's a great cooler anyways.
As for your CPU I like the new Piledrivers, I really do, but for gaming Intel is still better. If your build was budget, I'd understand, but considering you are opting for a 990FX MB and the most expensive piledriver, it'd be better to go for the Asrock Extreme3 Z77 and the i5 3570K.
Check out my $850 build here:http://www.squidoo.com/electronicandmore#module147086871
Just swap the 7870 for the 7970 and, IMO, you'll have a better overall build.