A number of things pop out immediately.
- #1: The whole platform (LGA 1366 vs LGA 1155).
I understand LGA 1366 is still Intel's enthusiast platform, but you should really look into Intel's brand new platform, Sandy Bridge (LGA 1155). While it lacks the triple channel memory compatibility of LGA 1366 (which is pretty useless unless you are really into synthetic benchmarking), these new chips are faster clock for clock (around ~5%), overclock much
better (I've seen 5 GHz+ overclocks already), they are built around a new manufacturing process (32nm vs 45nm), which basically means, incredibly low power consumption and heat generation.
There are a number of reviews around. You should definitely take a look at Sandy Bridge.
Thermaltake's Frío costs around ~$58, and it performs MUCH better than Cooler Master's V8, in fact, a number of review sites claim it's the best air cooling solution for the money.
12GB is 100% overkill. 4GB is more than enough really, 8GB if you feel 4GB is not enough.
While those HD 6850's are good/solid gaming cards, multi GPU solutions = big no no in my book. Instead of just enjoying games or whatever, you'll be spending most of your time setting up games and such to work for both cards (not to mention the dreaded micro stuttering present in SLI/CrossFire setups). Every friend I have that at one point or another have ventured into multi GPU solutions, they all end up saying the same thing afterwards, 'it's not really worth it'.
Going after the fastest single GPU solution is the way to go IMO. Which in your case would be, either the GTX 570 or HD 6970. And my recommendation would be: GTX 570
NVIDIA's Fermi based cards, sport much better all around performance under heavy AA/tessellation vs AMD's latest HD 6800/6900 cards.