I'm actually building one right now with a 24-bit/192kHz DAC board on it. I'm having some difficulties getting the DAC to work with video playback, but everything seems to run just fine. RaspBMC did a big update it looks like, so it may have made things a little more streamlined. It looks like a lot of people are seeing positive results from overclocking to get an extra 100mHz out of the Pi.