Inspired by Martin over at gHacks, here's my list of Firefox browser add-ons that I consider essential:
Mouse Gestures RedoxNavigate back and forward, close windows, and more with just the mouse. I turn on "mouse trails" to make it easier to see what I'm doing.
Easy DragToGoDrag a link to open it in a new background or foreground tab.
Adblock PlusBlocks ads, and is very configurable. Having a little "block" link I can click next to images and flash is extremely handy.
FirebugIndispensable for web development, especially the...