For those of you who are having issues with PulseAudio in 8.04 Hardy. I was able to get 5.1 surround sound working again with my Audigy 2 ZS by removing the following packages:

gnome-orca
gstreamer0.10-pulseaudio
libgnome-speech7
libpulse-browse0
pulseaudio-module-x11
pulseaudio-utils
ubuntu-desktop
pulseaudio
pulseaudio-esound-compat
pulseaudio-module-gconf
pulseaudio-module-hal
libpulsecore5

I then downloaded and installed esound and the alsa libraries and rebooted the system. I then had to add the front, surround, center, and LFE controls to the Volume Control and slide them up. I'm no expert by any means, but it worked. Ironically 5.1 sound worked with pulseaudio when using the lackluster onboard ADI SoundMAX HD audio. It was detected as NVIDIA though.