As the title says I would like to know wich of those 2 GPUs will be the best choice, I will be running games (such as Battlefield 3 when it gets realesed, Crysis 2, and the new-coming games) at 1680 x 1050 Resolution, I was decided to go for the GTX560 Superclocked but due to the Mobo I'm going to buy, wich does not supports SLI, I thought I should pick an ATI (Mobo supports Crossfire).
I'm not planning to run 2x GPUs at the moment, but in the future I might Upgrate to 2x, so that's why I haven't decided yet about wich GPU to buy... anyhow if the HD6870 is better/same in performance I would just buy that one... if not I have 2 options: 1- Pick another Mobo (same Proccesor tho but not in bundle =/ )... 2- Buy the GTX560 and Never be able to Run SLI
The GTX 560 and HD6870 are very similar in performance.
Is there a reason you have picked such an expensive model for the HD6870?
For the PSU I would stick with a good brand like Corsair, Antec or Seasonic.