Is this a reasonable Audiophile Mac-based Server?

You might also look at the Slim devices transporter.

Looks good to me. This is nearly identical to my setup. However I use software on a Mac Mini to control multiple CD players as the source rather than iTunes/hard drive source...of course my setup is 7 years old and, at the design time, ripping a thousand CD's to lossless files was impractical (costly)...ripping to a hard drive still remains a daunting task for me one day when I eventually go to a raid server based source (which I certainly will).

Being able to sit in the listening chair and select and cue music and surf the web for information about the artist and/or musical piece that I am listening too is simply wonderful ( I feel like Austin Powers - yeah Baby!) - certainly better compared to fiddling with CD Jewel cases and feeding a CD tray and punching buttons to select the appropriate track to play all of which just gets in the way of the music)...

FWIW - I think your solution is well thought out.

Restock,
I called Benchmark's technical support and spoke to them at length about your assertion that USB is superior to Toslink coming out of the Airport Express. They assured me repeatedly that Toslink would be "identical" to USB.

That allows me to save several hundred dollars by skipping the USB.

Incidentally the Benchmark staff is great on the phone (as well as online).

Last time I checked, the USB port on the AE is reserved for print server duty and it isn't able to stream audio. Now, that may have changed but I don't think so.

Your set up is very well thought out. And, good grief that's a lot of TB's! Do you have the fmaily movie collection on that thing?

If you're anal about sound quality as I'm assuming you are given your post, I have some suggestions: as Restock pointed out, the weak link in your system is the AE. Even with DAC, it is not going to sound nearly as good as a computer hardwired to the DAC...at least based on my trials. The other issue is that your tunes are making 2 wireless jumps which may cause problems from time to time, although I am so thoroughly impressed by Apple's wireless applications that it may be fine. My suggestion would be to put your laptop on your rack hardwired to the Benchmark via USB, toslink, or whatever. That will exclude the AE in your main rig at least and cut out one of the wireless jumps. The laptop can be controlled using Frontrow, or even better, an Itouch with third party software.

Also, as it seems money is not a significant limiter, ditch the Benchmark and step up to a better DAC.

We all know how incredibly difficult it is to put a CD in a CD player, sit down on our comfy chair and with this amazing thing called a "remote", hit the play button. And if you don't like the track you're listening to, this devise called a "remote" has a button called "next" or "forward" that takes you to the next track on the CD. It's just insane. Or of course, you can sit on your comfy chair with you laptop on your lap (getting hot) scrolling up and down your list of thousands of track titles trying to decide do I want to listen to this or not, dragging it over to your playlist, over and over and over again. 20 minutes later you've finally completed your selection to play. Yeah, this doesn't get in the way of listening.