Removing (actually renaming /usr/bin/pulseaudio) fixed my sound problems, too. Sound was working on Jaunty, then I upgraded to Karmic today, and Exaile and Rhythmbox both threw errors when attempting to play a song. Two errors were thrown: "data stack overflow" and "pa_datastream_size" error. video sound worked until Exaile or Rhythmbox threw one of those errors and then video sound would break, too. Re-login, video sound work, try to play a song, it would throw an error, and video sound would go out again.
I finally renamed /usr/bin/pulseaudio to effectively remove it, rebooted and no sound problems anymore. Sound card is on-board Realtek ALC1200.
I imagine there is truth to Pulseaudio's repeated defense it is flaky drivers and not "us," but why in so many cases when the same drivers are used with ALSA the problems disappear? No disrespect for the pulseaudio developers, but they do seem to be a little bit defensive.