Sounds like you are intent on Asus....a safe choice IMO. If you are looking at those boards, I'd wait for the A7V266-E, the one with the KT266A chipset. Performs better than both of them, but will cost a bit more b/c its the new version. Should be out in a few weeks. I think the A7V266 and the A7M266 perform about the same, the A7M used to cost a ton more b/c of the AMD 760 chipset, but I think the prices are both around $150 now. If you can't wait for the KT266A board, its kind of a toss up.
Chiz