$profile_dir/chrome/userChrome.css
/* Tab bar below Navigation & Bookmarks Toolbars For best results, show Title Bar or Menu Bar */
#nav-bar { /* main toolbar */ -moz-box-ordinal-group: 1 !important; border-top-width: 0 !important; }
#PersonalToolbar { /* bookmarks toolbar */ -moz-box-ordinal-group: 2 !important; }
#TabsToolbar { /* tab bar */ -moz-box-ordinal-group: 3 !important; }
I also prefer the old style menus so I re-enabled them with View->Toolbars->Menu Bar.Another quick tip: those big ugly spaces between the buttons and the address bar can be removed with a simple right click->remove on the empty space.