If you like to take advantage of the Firefox full screen function, then FullerScreen is a plugin you should definitely check out.

The plugin takes the existing full screen function and removes the menu, toolbar and tabs from across the top of the screen making the page you are viewing, truly, take up the full screen. You can easily access the hidden components by moving your cursor to the top of the screen where they will be become visible again.

Be sure to give this plugin a try.