Being a kde user myself and not familiar with gnome, I fear I don't know where to find your sound preferences.
But as for your pulseaudio issues, check here : http://www.gentoo-wiki.info/PulseAudio#Configuration
- it may help you out.
In general, pulseaudio will not lose any of your hardware sinks from version to version - especially if all your modules are up to date and properly compiled, as you can be realtively sure they were with entropy. It is however common for a pulseaduio update to accidentally knock pulseaudio off the autostart list, especially if pulseaudio had to be killed during the update and was then restarted manually. If this happens, then any app that wants to use the soundcard will bypass pulseaudio completely and monopolize your card, making it impossible for any application, including pulseaudio, to use the card. This may be what happened to you when you tried to restart your sound server.
So try restarting the computer in order to kill any process that may be hogging the soundcard, and launch pulseaudio as your user from a tty before logging in. If it still fails, that means you do indeed have a library or configuration issue. If it works fine, then you just had an app monopolizing your soundcard before. Also, be sure you check to make sure pulseaudio isn't running before you start it - if you start a second instance of pulseaudio, even if the first one is defunct, you'll see a ton of error messages regarding failed sinks, failed priorities, and stale PID files.
As a final addendum - I personally no longer use pulseaudio, as I found it not nearly good enough for my needs. I use jack-audio-connection-kit, which is a similar sound server, and it works wonderfully, especially with the tool qjackctl to configure it on-the-fly and in gui mode. It takes a little while to set up on a Sabayon machine, but once it works you'll love it ever more than pulseaudio. If you want to go this route let me know.
Hope some of this helps,