Re: Anyone using a USB DAC...
I use a USB DAC in my reference two-channel system via the Bel Canto e.One S300iu integrated amp. Being able to simply plug in my laptop to my two channel rig and cue up thousands of songs is very cool. I rip all my discs in lossless formats and through the Bel Canto stuff I can not hear that much of a difference (if any) between the digital files and spinning the discs themselves.
I also use a USB DAC at my office via Outlaw Audio's RR2150 stereo receiver. Again, I simply run my computer straight to it and play music all day long.