I saw a post on lifehacker yesterday about widefox. It is a configuration of Firefox using the TabMixPlus extension and a custom userChrome.css file, that puts the tabs labels down the right or left side of the browser. If you have a wide screen. This is a much more efficient use of screen real estate. Very few web pages look good as wide as 1600 pixels and the default tabs use valuable vertical real estate. You can get many more tabs visible at once this way also.