Digitalmeisters - Thoughts on Olive.....

Airport express is a router with increased connectivity compared to standard routers. The WiFi signal from AE (or any other router) will then be captured by any device capable of receiving a Wi Fi signal. Alternatively, it can be directly connected ("wired") via it's ethernet or other connections to a device that accepts
a similar connection.
I have my AE in a closet in my upstairs. It beams a WiFi signal to my MacBook
downstairs. My MacBook is physically connected to a DAC (via firewire in my case, most people will be using USB or S/PDIF). My DAC is then connected by RCA stereo jacks into a receiver.
Some DACs are capable of receiving a WiFi signal by themselves. Logitech Squeezebox is such a device (and then it has other functionality to bring to the party).
I hope the above is not to confusing.

No, that is clear. Thank you.

Two facts about using Airport Express with iTunes on Mac: (1) it is bit perfect, if you disable volume control in iTunes prefs; (2) it converts all lossless audio to Apple Lossless before transmitting (and then back to uncompressed SPDIF at the optical TOSlink output).

You might consider putting the digital output of the Airport Express through something like the Genesis Digital Lens to reduce the jitter. I found it made a big difference with my Mark Levinson 390S. Of course, more modern DACs have jitter-rejection schemes built in (Benchmark, Bel Canto).

I was in your situation about 4 years ago when I decided to sell my Accustic Arts CDP-1 and migrate to a computer audio source. It was a disappointment at first with USB DAC's from computer type cheapies to $1800-$3500 priced units. That was a wake up call. I realized I would need a comparable DAC to match, if not exceed, what I was accustom to hearing with my prior CDP. And based on your digital source I think it's safe to assume you're in the same situation, unless you're looking to downgrade. I eventually ended up with a Reimyo DAP-777 and Wadia iTransport/iPod (Apple Lossless) after being quite impressed by what I heard with a SB3. That served me well for 2-3 years. Now I'm currently looking for another solution, one that has a better, larger GUI and simple one-box design. I've always wanted to use my iMac/iTunes but still not convinced with USB converters, not that having my iMac on top of my audio system is ideally what I want. iPad is what I want to control playback so I'm considering the Meridian/Sooloos Media COre 200 or Bryston BDP-1.
I considered Olive in the past but didn't care for their proprietary design, SW (WIN?), and small GUI screen, nor the fact I'd have to re-rip all my CD's. And if I did use one it'd only be with a DAC.

So here's my advice; audition what you can and don't waste time with AppleTV and Airport Express. It's garbage (Optical/Toslink), regardless of the DAC used. Take it from experience. And since you already have a highly regarded DAC you're half way there. Personally, I doubt you'll find a satisfying USB/FW DAC unless spending over $5K (such as the Weiss). If you have a Mac or other computer I would try USB converters (Evo, Wavelink, Stello U2,..) to hear what you think. Your opinion is the only one that matters. This is far more subjective with sound, GUI, set up,..etc as well as system integration, compatibility then with other audio gear. You really need to experience it, hear it, see it, interact with it, to know if it's right for you. You may not like the interface, or it may require being wired (ethernet) and you don't have a router near by, or it doesn't have the connection you want/requires,..etc. It's computer based. What'd you think. ;-) Take your time if possible and audition, audition, audition.

Thank you Sakahara.