I would get either a 560 ti or a 6950.
Benefits of Nvidia: 3d gaming and physx (better explosions, debris, etc.). benefits of AMD: 3+ monitor support on a single card
The 6950 performs slightly better than the 560 ti. Although individual game performance will vary.
For the gtx 560, I would get the MSI N560GTX-Ti Hawk GeForce GTX 560 Tihttp://www.newegg.com/Product/Product.aspx?Item=N82E16814127578
For the amd 6950, I would get the sapphire 6950 dirt 3 editionhttp://www.newegg.com/Product/Product.aspx?Item=N82E16814102945
As for PSU, that is a great PSU but if you could buy this equally good 750W psu:
Corsair HX750 and save $20http://www.newegg.com/Product/Product.aspx?Item=N82E16817139010&Tpk=corsair%20hx750