I just completed a dist-upgrade from Intrepid to Jaunty. Everything worked except I needed to reinstall OpenOffice and rerun
sudo apt-get install ubuntu-restricted-extras
VirtualBox was OK but I needed to select More>Backup to cope with a changed format.
My surround sound was gone though. Fortunately the answer was dead easy. See http://www.automaticable.com/2008-05-28/how-to-enable-surround-sound-on-ubuntu-hardy/.
Basically you uncomment one line in a file and change a 2 to a 6. No need to muck around with Preferences and sliders etc.