I just quoted this system to another guy, which came out to about $920. That right there is sort of the sweet spot for price/performance. If you're willing to spend that much, I'd take that build, throw in an SSD (Change HDD from Black model to Blue model), and maybe look at a 670.
However, I currently use a lower card than that (GeForce 660) and with that CPU, I can run 25mans at effectively 60fps stable on Ultra.