That will remove it from the panel but if you want your menus back,
open gconf-editor in the terminal. Type:
gconf-editor
then navigate to
/apps/gnome_settings_daemon/gtk_modules
There you should see two entries for globalmenu. Just un-check them.
Nautilis has its own setting though. You'll have to click on the wheel to the far top right of a window and then select "menu bar."