I have just stumbled on one of the greatest/most useful plugins ever made for FireFox. The name: Ubiquity, and it is from the Mozilla Labs. Basically it is this little shortcut (Ctrl-Space for me (Windows default)) which brings up this menu which allows you do control every aspect of FireFox from it; you can close tabs that you don’t have open in a flash (faster than Ctrl-Tab (multiple times), Ctrl-W), perform google searches, wikipedia searches, and many, many more downloadable from the net. For those who have used Quicksilver on Mac it has similar functionality to that.

Link to it’s home-page is here: http://labs.mozilla.com/projects/ubiquity/