nsheldon wrote:.... The AirPort Express has optical digital audio (mini-S/PDIF) output as well, so your entire audio path (from iTunes to the AirPort to your amp) can be entirely in the lossless digital domain (though limited to 16-bit/44.1 kHz).
Exactly, and most people, unfortunately, will not be able to hear any difference between this setup and hardwired setup. The problem arises (for those that can hear it), not because of the specs, but because of the practical implementation. Going over wireless can and usually causes timing issues in the data. The issues are automatically corrected and anomalies are produced. Again, most won't hear it, but its really obvious if you know what to listen for. With that said, we use exactly this setup for whole house audio and TV audio (both non critical listening). We do however use a hardwired solution for our home theater and music listening.
<Off Topic Rant>
I point this out because I personally believe that the lack of critical listening desires and skills is one reason today's music is so poorly mastered. I won't buy a lot of music produced today because its mastered for ears that can't or don't want to hear the unnecessary distortion and lack of dynamics. This is not meant to be critical, but rather to inform. Listening skills are learned. But how many people set down and listen only to music for hours at a time. So in some ways it's a result of our time, but again its not good.
http://en.wikipedia.org/wiki/Loudness_war<END>