Well I just built my rig and I am satisfied with the results. Have an i5 3570k, Sapphire Radeon HD 6870, Asrock z77 extreme 4 mobo, HAF 912 case, & OCZ 600w power supply. Do not plan to do any overclocking for a year or two. Plays Guild Wars 2 no problem, but struggles a bit to play BF3 on High. I do like how cool the sapphire runs though.
I see the GTX 560 is only $210 ($40 more than the Radeon) - $180 with the rebate included). Only problem is my 6870 is obviously open and has been used. I have never returned something to Amazon, so I am not sure what kind of fees I would be facing. I am well within the 30 day return period (anyway to get around the restock fee?).
Just not sure if it would be worth the hassle to get this and return the 6870.