i dont know about MSI boards
and get CPU with L2 = 1MB (preferred) on 939 pins, and whatever u buy, prefer VIA over nForce-3, i know n-Force-2 was real blast in AMD AthlonXP performance, but this time VIA took the lead.
i've been using Asus for a long time, so i can only recommend Asus. as now every system in my home is based on Asus (1 on Giga-Byte)