No sound with Gnome 3 and pulseaudio?

Dear Lazyweb,

I recently switched from KDE to Gnome 3 and I am so far very happy with the decision. One thing that bothers me since then is that the sound does not work when restarting the computer or waking it up from suspend. After a while I figured that a simple sudo killall pulseaudio fixes the problem -- but only until the next reboot. Has anyone a hint what the problem could be/ I found quite a few similar problem descriptions on the internet but with no satisfying solutions so far.