Are you tired of looking at the default Firebox menu and address bar? You could always change the theme, but that would also change the look of the navigation buttons and menus. If you want to change the way Firefox looks, but keep the same navigation layout, consider adding a persona to Firefox.
Personas are graphical "skins" that are applied to the menu and status bars of Firefox. Instead of the default grey background color, you can customize the background to feature various designs. For example, here is Firefox using the Golden Gate Bridge persona:
Personas are easy to use and just require a simple software installation. To get personas for Firefox, go to getpersonas.com.