Is this a reasonable Audiophile Mac-based Server?

You should be able to try it both ways to see what works best. I got into this whole thing by trying airport express. It didn't work in my system, but as others have pointed out, that could be the exception rather than the rule.

Try it. If it doesn't work for you, return it to the apple store. Cat5 cable is cheap and easy to test too.

My system ended up being hybrid wireless. Ethernet connections from network drive to router to music server (sonos) then to dac. Wireless laptop controls playback. Simple and reliable.

Just stick a SB3, sonos, transporter or mac mini next to your dac and you'll have great sound that you can control from your listening chair wirelessly with your laptop.

Don't do anything that takes the laptop away from your lap or binds it with wires when it is there. There is a simple way around it.

I use a wireless keyboard with roller ball mouse. I use my HDTV as a screen. (Mac Mini can output 720P with some slight mods to the software that controls the video card)

But feel free to ignore this as I did quite a bit of programming for my setup so that I can control everything (even switch on and off any components using my Mac from my wireless keyboard at the listening position). My setup is for the more technically inclined.

Hdomke -

the wireless system may or may not work to your satisfaction, there is no question that the wired system would. What it would sound like is skips - same as a wireless phone or cell phone losing the connection. Obviously it works well enough to satisfy most people most of the time. But you asked about the ultimate which it is not simply for reasons of absolute reliability - no doubt it is a whole lot more convenient.

Since the performance is location specific the only thing to do is try it - after all you know you have a back up plan.

In describing your Apple (which sounds way cool)I think you are mixing your technologies. Airport Extreme is the same as WiFi - technically it is called the 802.11 standard. The newest version of the standard is "n" - as in 802.11n. You can read a nice description on Wikipedia - basically its the next evolutionary step - faster - but also able to handle more clients at once which you really don't benefit from in a home like you would in an office.

Gigabit ethernet has nothing to do with WiFi. Ethernet is a different communications protocol based on wires. The confusion comes in that some devices such as the Squeezebox can handle both Ethernet and 802.11.

Ethernet comes in several flavors (speeds). Most installations use what is called 10/100 which refers to how many bits the ethernet router can handle. Gigabit is a much newer standard and because of its greatly increased bandwidth (data carrying capacity) is preferred in SOTA installations that require high bandwidth - just for the record, audio does not need high bandwidth.

The Squeezebox or any of the other products from SLIM Devices, would basically replace the link from the Mac to the DAC. Because they are on Ethernet (or WiFi) the software enables you to use a remote control to control the SLIM box from your easy chair, just as you could use a remote to control the Mac mini.

A NAS is a network attached storage device which is a node on an Ethernet network. Thus my slang about "hanging it on" meaning it would have a unique TCP/IP address. A NAS is cool (and arguably the ultimate) because you can install the SLIM software in it and run the music system without needing your computer to be on at all. Check out the SLIM site.

Props to you for doing your homework and laying it out on paper - I am sure you will come up with a great system.

Restock's experiment is inconclusive. When you have multiple variables in an experiment it is impossible to determine which causes the effect. The conclusion that USB is better than toslink ignores the fact the transporter may be introducing large amounts of jitter. This may be the cause of the inferior sound and may have nothing to do with toslink. A better comparison would be

1. Mac Mini feeding Benchmark DAC1 via USB
2. Mac Mini feeding Benchmark DAC1 via toslink

even though this isn't conclusive either since despite what Benchmark says the DAC may indeed work better with USB. This isn't saying USB beats toslink every time, only that the Benchmark may be better with USB.

All I can say is that in my system ....XP computer - wireless - Airport Express - toslink - Altmann DAC the sound is fabulous, jaw dropping, stunning, ..(insert your own adjective here)

Amazing all the conjecture against Wireless 802 system and in preference for USB.....IMHO both should sound indistinguishable provided you buy modestly good gear...after all none of this is rocket science...do we really suspect manufacurers are all inept and incapable of building something that works.

What happens at the clock in the DAC itself is anyone's guess in a specific setup with your house mains power and whatever other applicances you have connected - but rest assured that most manufacturers are building perfectly good gear. There is no reason to be assuming the worst from teh outset until you find a problem. There is no cause for such fears from the outset.

As for me, I would build it and then cross check it against a CD player direct into the amp (using exactly the same test tracks as on iTunes) - that is what I have always done in the past (switching back and forth with the remote endlessly until I am satisfied I have no idea which one is which). If you can't hear any difference after this kind of extensive auditioning then it is good enough to stop worrying (just make sure to precisely level match volumes as even a very slight increase in loudness sounds better)