Oh yeah, i remember! Welcome Back!
Is everything going well? Build go smoothly?
Just skimming over the build again, you could drop the mobo down a bit and save some cash, the only difference is the fact that your board has 2 x16 PCIe lanes, wheras mine has one, which splits into 2 x8 lanes when 2 cards are used.
If you are only really planning on using one gpu, then you might aswel drop down. Even if you use 2 cards, the performance drop on a card between an x16 and an x8 lane is about 4%
GIGABYTE GA-890GPA-UD3H - $139.99
http://www.newegg.com/Product/Product.aspx?Item=N82E16813128435
Then just get the OS at standard prices - $100...