Gigabyte and ASUS are the two top motherboard manufacturer's. ASRock is part of ASUS's family so their support should be equally as good. You'll be fine with any of these motherboards, which I would lean to the ASUS and Gigabyte UD3R out of all current X58 motherboards.
Thanks, I'm catching up on things. I used Asus exlusively for mbo's to build hundreds of PC's in the IT installation that I managed but it was ten years ago and I wasn't sure if any of the other mbo vendors were of the same quality. I have compared the UD3R to UD7 and Asus Rampage III and it seems like the best choice from a price/performance view as long as the build quality is somewhat equivalent. I don't see that the more expensive boards buy you that much more.