If you've customised the Gnome panels in Ubuntu 9.10 and then changed your mind it can be quite difficult to get the original layout back. This guide explains how to reset the Gnome panles in Ubuntu 9.10 to their default layout.
Start by going to Applications->Accessories->Terminal (if you have deleted the menu you can get to the terminal by pressing Alt+F2 and typing "gnome-terminal").
This command will unset the configuration values for the Gnome panels. You will lose any changes you made to the panels.
gconftool --recursive-unset /apps/panel
Next you will want to delete the configuration keys:
rm -rf ~/.gconf/apps/panel
Finally, to close and restart the panels run this command:
The panels should now re-appear with the default Ubuntu configuration.