That's a super important one. Audio on Linux/Ubuntu is okay, but when you run into serious troubles you're screwed. Nobody can help you unless you pay someone, other options: get a new computer, install a different Ubuntu, distribution or switch to Open Sound System. The only thing that always worked through all the years but it has obvious drawbacks.
Hmm, I've done well enough (on Debian testing) by enabling dmix in alsa and sending sound through alsa by default and letting pulseaudio start on demand for the applications that insist on it: mainly, this setup lets mpd continue playing after my graphical session ends.
