Go ahead with the X4 970 if your budget is doing OK.
Checking your other thread and I see you already have that Xigmatek Loki cooler.
I was going to suggest the X4 955 and a CPU cooler for overclocking.
Since you have the cooler already you don't need to save the $30 by getting the X4 955.
And you already know how well the GTX 560 Ti can OC.
This is with a stock 560Ti vs HD 6850 in BF:BC2