If you like your browser interface to be simple, try these extensions designed to unclutter Firefox. Compact Menu 2 and two alternative extensions collapses all the menus into a single drop-down button, creating room for you to add buttons such as Downloads, History, and Bookmarks to the menu bar. Organize Status Bar lets you rearrange all the items displayed on your status bar, or even hide some.
To install the Compact Menu 2 extension, click the Install Now button on its home page. Unlike most Firefox extensions that need to restart the browser before they work, Compact Menu is automatically enabled, but it won't replace the existing menus without your explicit instructions.