Not much difference between those 2, but I'd get the Asus board simply because I've had 0 problems with them in the past, and it costs less (in the US at least).
There is nothing like a gaming motherboard. Those high end motherboard usually serve SLI or CrossFire as the main purpose. Other than that it only affects if you are going for an overclocking tournament or you want to brag about your benchmark scores on the internet. It doesn't affect gaming visually to the human eye.
I would say that rig is heavily unbalanced. Even if you have a 720p monitor the HD 7770 is still very weak compared to the CPU. And if you have a 1080p monitor that is out of the question.