I am on the computer all day since I play online poker for a living, but I want to be able to run new games without any problems. It would be nice to have upgrade-ability to be able to drop in another 6950 in crossfire or something sometime in the future. I game at 1900x1280, but could possibly upgrade to a higher resolution monitor sometime in the future.
I already ordered these during a Black Friday sale:
Antec Earthwatts Green 750W Power Supply ATX12V V2.3 EPS12V Active PFC 80PLUS Bronze 135mm Fan
Corsair Carbide Series 500R Mid-Tower Gaming Case ATX 4X5.25 6X3.5INT USB 1394 No PS White
1. I would go with the gtx 560Ti, it's comparable to the 6950, but is a little better frame rate wise. Also the different companies make different fans and heatsinks for the gpu, so the cooling might be different. Also different companies have different warranties. Since the actual GPU is the same, I would look at which has the best warranty.
2. ASRock Extreme one because it can CF AND is a z68 chipset.
3. Yes, the CM Hyper 212+ allows you to OC the CPU to around 4.1-4.4GHz and run stable.