I don't know which motherboard to get.

Solution
Hello,
How come you're buying a cooler without OCing? Won't really give you any benefit, you're better off spending the cash on the GPU. :)
Anyway, here you are :) ATX is a good idea, especially in the Phantom 410 as you have plenty of upgrade options and it'll fill the case properly. http://au.pcpartpicker.com/p/2G8qrH