Two things need to be addressed. The quality of the motherboard, and the compatability issues with the chipset.
All of the current Athlon socket A boards will be using different flavours of VIA chipsets, and possibly AMD chipsets. The KT133 is a popular and relatively new one.
I've built many machines based around the Asus A7V and the ABIT KT7. Both boards are good as far as quality and stabilty go.
Outside of getting a decent namebrand motherboard, your other concern should be what hardware your going to use.
There are compatabilty problems with the VIA chipset boards and many pro-sumer sound cards, among other hardware, videocards etc.
So, the bottom line here is. Athlon is a good platform for recording, but... Carefully research your hardware before hand to make sure it will operate. Do this by going to the soundcard manufacturer website and reading to see if there are any known issues. I find the phone works better for this type of thing. I don't know what soundcard your thinking of buying, whether it be Aardvark or M-Audio, Lynx, Echo etc.. but all of these companies are easily contacted and should be able to answer your questions.