If you could find a 6870 at the same price range of a 7770, I would definitely go for that. A 6870 creams the 7770 in basically everything.
I'll just get the hd 7770 because the 6870 is probably harder to find since the 6870 is older. Anyway, thanks for replying guys! I really appreciate all of your help. I'll edit this post once I get a 7770.