/etc/alsa/pulse-default.conf (from alsa-plugins-pulseaudio) sets pulse to be the default ALSA device. This results in users being unable to play sounds unless they start up pulseaudio. GNOME and KDE do this automatically, so it happens to work in most cases, but it breaks sound for any other use cases. Either pulseaudio should be started as a system service, or the ALSA default should not be changed unless pulseaudio is running.
Also see the discussion in bug 388971.
*** Bug 388971 has been marked as a duplicate of this bug. ***
Had this problem: I could not run any but a few sound apps when I installed F8. Turns out it was because PA was not running, so I was running it in the commandline for a while not knowing where it should actually be started. I had an old /home-dir and ESD was diabled. No warning about this, no clue that not launching ESD would affect PA. (I think a lot of people will have something like an old /home on a network share, with ESD disabled ESPECIALLY RHEL users so this is a real blocker when RHEL forks from Fedora.) Then it turns out that ESD == PA (atleast for GNOME users). So now I solved this. But not having audio until realizing this was a bit painful. See also bug 425501. (BUT: Lennart, it is worth the effort and PA is super cool, so don't loose the spirit because of all these roadbumps!)
I don't think it is right to use tha PA plugin for ALSA only when PA is running. This hides bugs (and also breaks autospawning for those who use it).
Changing version to '9' as part of upcoming Fedora 9 GA. More information and reason for this action is here: http://fedoraproject.org/wiki/BugZappers/HouseKeeping
PA in rawhide now enables auto-spawning by default. This bug report is hence obsolete.