Well, Gigabyte is really good mobo and has one of the best solutions for cooling in the market. The P6T Deluxe v2 will be very good if in the future you plan to use like 3 graph cards. Really it comes down to ur budget and the giabyte is most likely goin to be cheaper but the Asus motherboard has that peak end perfromance that u will probably want in the long run.
Another good solution to a mobo for ur combo is the Asus P6X58D-E mobo. It has USB 3.0 and SATA 6.0GB/s if you are interested in that future stuff.
Yeah I second the P6X58D I have this MOBO and it is awesome! OC's well and the only complaint I have about it is that the back plate has some insulation or some padding or something on it and I really had to push to get the screw holes to line up towards the back or the board. Although that could also have just been a miss alignment by a bit with my case maker? Also if you go crossfire you will not be able to use any on the pci slots if they are dual slot cards. You will have a pci-e at the very bottom for maybe a sound card or a single slot nvidia gpu for physx and one of the smaller pci-e slots at the very top that could maybe run a sound card or internal wireless card or such.
So, it looks like the P6T is better for crossfire because the two pci slots in between the pci-e's give extra space between cards, thus better cooling. is it really a problem on other boards to have the graphics cards so close together? if it was so important, wouldnt more boards have the pci-e pci pci pci-e arrangement?