It sounds like compiz is working for you. The "disappearing panel" could be the result of the opacity plugin, called "Opacity, Brightness, and Saturation" in the Compiz Config Settings Manager, with the panel being matched and set to to "0" opacity (invisible). It's a little strange however, because this would not be part of the default configuration.
That plugin is the most likely cause of the panel "seeming" to be gone.
To double check, when you run compiz, run "ps -ef|grep gnome-panel" ... it should be running:
[charles@dolphin]$ ps -ef|grep gnome-panel
charles 2499 2400 0 Sep13 ? 00:00:17 gnome-panel
charles 24325 3113 0 15:49 pts/1 00:00:00 grep gnome-panel
If gnome-panel is running (as in the above output) and you can't see it ... it's the opacity plugin!