Most of your issues will revolve around the motherboard chipset. And right now there is reason to question the use of the VIA chipsets for DAW use see Darth Via Article. So I feel its better to go with a mobo based upon the AMD 761 chipset rather than the faster KT266A chipset, and in some respects, its just marginally faster, and you may even want to put your dollars into the 762 chipset and be dual processing ready? The VIA's have problems.
There is no doubt that the current crop of VIA KT266A chipsets are among the fastest on the planet for use in a PC. But it is far wiser I think at this day to go with a motherboard that is proven to be rock stable and upgradeable, and that means the AMD 761 chipset. Manufacturers such as EPOX (EP-8K7A+ RAID), GIGABYTE (GA-7DXR), ABIT (KG7-RAID) and ASUS all make versions that are very good and stable.
I feel its best to stay one or two steps away from leading edge tech stuff. The boards I listed (to name a few) also have the RAID option, which means 2 more channels for IDE devices, which can slove many a conflict.
It would also be wiser I think to spend the money on memory, although I know you won;t be saving huge amounts going to the 761's.