I'm hoping Apple finally decides to give Airtunes the push it deserves. The "Killer App" for Airtunes is the Remote program on iPhone/iPod Touch. This thing is very cool for a version 1.0 release, and can only get better.
Here's what I'd like to see:
A new version of the iPod Hi-Fi, with an Airtunes client built it. Drop the iPod dock to distinguish it from the million other speaker systems out there and make it look more streamlined. Change the name and sell it for $249. People could buy more than one of these for different areas in there house. Drop in it, plug it in, control the "Zone" from the Remote program. Apple simplicity.
Also, Apple could make a slimmed down version of Airport Express. Call it "Airtunes" and it's only function is a client with an audio out mini-jack. No router, no ethernet jack, no USB. Airtunes only. Sell it for $49. That way people would have a cheap way to use their existing audio equipment (anything from an old boom box to a high end amp) to receive music from iTunes and have that "Zone" controlled by the Remote app.
The Remote app could be updated to version 2.0. Among it's features are being able to access a CD in iTunes, and call up various internet radio station. Also, fix the album art issue with Remote and Apple TV.
One last thing. Update Apple TV to allow the volume to be controlled with Remote app.