ive found that MSI KT3 Ultra boards are quite stable ... im running a KT4 right now after an upgrade from a KT3 ... i never had any real problems with it and they do come with built in 5.1 not greatest quality but hey it works .. some come with a Bracket that has optical and coaxial outputs on it but its only 2 chanel still good and no ground loops wiht optical
... for CPU coolers if you want quiet Zalman is the way to go (hope i spelt them right) their Quiet Maxx 5100 CPU cooler is wonderful its avilible at local compusa