Firefox only (Windows/Mac/Linux): Keep your menubar and its drop-down options accessible but out of sight with the handy little Hide Menubar Firefox extension. If want to keep the menubar around but don't want to have to go through the hassle of right clicking and activating it every time you need it, Hide Menubar is a great compromise. Until you press the ALT key, the menubar stays hidden giving you that sliver of screen real estate back. When you need one of the menus, it's a keystroke away. If you have your own trick or favoured extension for stealing back your pixel space, share it in the comments.