How about an Abit NF7-S, it's a good overclocker and has the Soundstorm audio and Firewire. And it's earned a good reputation overall.
For the power supply, if it's an older one or a sort of cheapie brand, then you might be wise to upgrade to a quality brand and some additional wattage. An Enermax, Fortron or Antec in the 400W+ range would leave you some breathing room if you go and pile in a bunch of storage drives and a higher-end video card as time goes by.
Bigger picture: thought about an Athlon64 instead?