Nice with what you have there
I agree on the motherboard completly, as I have it on this build I'm running off now, with an overclocked Core 2 Quad, running at 3.2ghz, though its capable of reaching 3.6ghz rather easily too.
CPU is also rather nice, and can't really say anything bad about the RAM/hard drive or DVD drive.
Rosewill I've heard are okay, so that power supply shouldn't give you any issues either.
What is the video card you'll be running with?
I haven't tried the onboard sound on the motherboard, but it should be sufficent.