The gigabyte board can sli while that asus cannot. But there are a number of better boards at that price. http://www.newegg.com/Product/Product.aspx?Item=N82E16813157293
Here's the extreme4 that was suggested.
I would suggest you make a post in the system section and filling this out so we could help pick all the parts and find better deals. http://www.tomshardware.com/forum/353572-31-build-upgrade-advice
@wanderer atx and microatx standards are both 9.6" wide. The extreme 4 is thinner but not to be confused with microatx standards.