You know, you could get the 5970 AND the 5870 and crossfire them. I don't think that 2600k at 4.8 is gonna really bottleneck them. Granted, you won't get the same increase in performance going from 2 GPUs to 3 GPUs as you would going from 1 GPU to 2 GPUs, but you'd still see a gain.
“Never underestimate the predictability of stupidity.”
“Amd....definitely a blond female.....not much on the cpu side, but always strutting about showing off her gpus......wow that was bad. I apologize.” -ensabrenoir