I installed Ubuntu 9.04 on my new AMD64 laptop and tried to play some music. Aqualung (my preferred player) did not work properly with Pulse's ALSA emulation. For example, switching tracks caused a delay of several seconds. Next I tried to switch to Audacious, but it also behaved weirdly, and the sound quality was horrible. I also think I had problems with other applications. Next, I got rid of pulseaudio and suddenly everything worked 100%. Just reading this thread shows that this is not an uncommon experience. Conclusion: Pulseaudio is not ready to be installed by default on desktop systems.

Looks like it's gonna be one hell of a rig.