Mac to... AE or Optical DAC or USB DAC? Also...

I'm working on a simple audio server and I'm considering all of the costs and options. I plan to use an iBook (or the new Intel version of this due out soon), but the Mac Mini is another option. Most of my music is in Apple Lossless.

I could go...

* wirelessly to the Airport Express and into my amp (cheap and easy)
* wirelessly to the AE into a DAC with optical
* direct from the iBook into a DAC with optical
* direct from the iBook into a USB DAC

Any opinions on these various options considering quality and convenience and any other criteria? The "optical" options allow me to still use my transport as well with the DAC using S/PDIF, but all options allow me to use the Mac as the CD transport if playing CDs.

How do the wireless options effect sound quality, if at all?

Also, if I were to use the Mac's CD drive as a transport for CDs which Mac is the quietest drive? IME some drives can be very noisy on the first few tracks of a CD.

Wireless doesn't affect sound quality IF you have a decent DAC that properly reclocks. (These days, most of them do, and you're more likely to find a bad one at the top end of the price chain.) AE straight into your amp is not a good idea if this is going to be your primary source. It's fine for casual listening or already-compressed Internet streams.

If you already own a transport, I wouldn't bother using a Mac for that purpose.
Don't use the computer as a transport. I would go wireless from MAC to AE then to DAC.