I have an I7 930 OC'ed to 4ghz. Is it worth upgrading for gaming?
Also, I want to replace my 6970. Should I wait until Nvidia's 800 series is released?
Are you unhappy with your performance in any particular game? If so, consider an upgrade to a 770 (unless you're above 1080P or want to be soon). If not, wait for the 800 series.
Once you have a new GPU, consider upgrading your CPU sometime (probably to Broadwell in 2015) a) because an i7-930 is still alright and b) because Broadwell-K will have better thermals than Haswell.
I would wait wait one more year before upgrading your CPU. Broadwell is around the corner.
I see to reason to replace a 6970 yet. It handles pretty much anything at 1080p doesn't it?