I'm iffy with ASRock. Yes, they are made by ASUS, but it's the budget version of ASUS basically, and that's not always a good thing. I've used plenty of ASRock boards in the past on customers' machines with rarely any problems. They work fine in normal everyday machines, but for people like us that like to stress and actually use our machines, I wouldn't recommend them. There are some nice Biostar boards that are pretty cheap at the moment, those would suit you pretty well.
Gigabyte is a good brand too, but tend to be a bit more expensive. It all comes down to what you want to pay.