Depends on price. For that kind of money, you could build a system based around either brands.
The i5 2500k performs better than the phenom 1090T in benchmarking tests, but doesn't mean terribly much unless you are aiming for a specific performance characteristic... That having been said, is BFBC2 optimized to hexacore? If you're only using 4 cores max (or 2 cores) it doesn't matter how many you've got!
Check out THIS
out. This is the graphics rating thread.
3 GTX 580
4 GTX 570
5 GTX 480
How much do you value performance? The GTX performs better than the HD6970... How much, I couldn't tell you... How that translates into fps, again, I couldn't tell you.
I can tell you the HD6970 is a big *** graphics card, I'd advise you to get a full sized case and a full sized mobo otherwise things might get a bit cramped in your case!
Price wise, Nvidia & Intel are more expensive. ATi & AMD are generally cheaper.
Get back to us with which way you wanna go and someone can put together some components for you. Or ask more questions
Hope i've helped!