It looks like the result of the "fix the Linux audio mess" discussion was to standardize on PulseAudio. Most people I spoke with at the Ubuntu summit weren't familiar with it; it used to be called PolypAudio and it's written by the guy behind Avahi. The Ubuntu wiki promises:
Beyond the obvious sound mixing functionality it offers advanced audio features like "desktop bling", hot-plug support, transparent network audio, hot moving of playback streams between audio devices, seperate volume adjustments for all playback or record streams, very low latency, very precise latency estimation (even over the network), a modern zero-copy memory management, a wide range of extension modules, availability for many operating system, compatibility with 90% of all currently available audio applications for Linux in one way or another.
What would be cool is for someone to hack the iTunes remote speaker support into PulseAudio as another network audio sink, so I could have used the mac as a dumb wireless speaker box directly.