Hey, I'm not sure if you're still taking suggestions but.. here's my revised picks from your original build:
AMD FX-8120, XFX Radeon HD 7870, Fractal Design Core 3000 - System Build - PCPartPicker Canada
I managed to squeeze in an SSD, FX-8120, 990FX board (990X originally), Liquid CPU Cooler (won't have a problem with your ram), and a better case for a total of about $830. I downgraded the 670 to an 7870. Well, "downgrade" would depend on whom you speak to, but the 7870 would be more than enough to play SC2 @max; not to mention the increase in performance from the new AMD drivers.
7870 reviews for SC2:
AMD Radeon HD 7850 & HD 7870 2 GB Review | techPowerUp http://www.tomshardware.com/reviews/...k,3148-14.html
And this isn't really a guide, but more of a trouble shoot forum for ocing the FX-8120 (might need it just in case, fairly easy to look up a OCing guide).
OC FX-8120 BIOS settings for a stable 4500 MHz