Think of it as Windows Aero/Linux's Copmpiz / Mac's Expose in your browser. You can preview and then open all your tabs via this extension in various 3D views. You can select from 6 Different Views to display the tabs. One intresting and very useful feature is you can switch to Foxtab view and it will show all the tabs from all the windows for easy switching in Full 3D glory. If you find yourself frequently working with more than 20 tabs, some of which were opened a few hours before and have difficulty in remembering what is there in what, this extension should significantly reduce your neural processing load.
Download the addon from here : Foxtab