With those three components already picked, your gaming performance is mostly already determined, regardless of motherboard. Any overclocking will not differ much among the boards. Pick the cheapest one from asus or gigabyte that has the features that you want. For future upgrades, you might want a mobo with two pci-e slots to allow for adding another 4870, but It will cost you more now to use a stronger psu. By the time you want more, a stronger card will be out.