Adblock w/ Filterset.G Updater -> No ads, no configuration. Win/win.
Fasterfox -> I turn off the pre-fetching but it is noticably faster.
Forecastfox -> It is nice to plan rides around.
Stumbleupon -> Ultimate time waster.
Better Gmail 2 -> Allows for gtalk at work when you force encryption across the gmail domain.
Foxmarks -> Good for syncing multiple bookmarks across PC's.
Greasemonkey -> Handy scripting utility.
mouse gestures is definitely the best one you can get....
it allows you to navigate firefox (back, forward, new tab, etc......) with just right clicking and dragging different directions.....so i can right click drag left and go back a page, or right click and drag in a 'z' shape and go to the next numbered page in a thread......
its a really slick item!
so now you can move even less when using the computer!