I have been using FireFox for years, though I still switch between it and Opera on occasionsome of the plugins I use are the spell checker, StumbleUpon (oh the hours I have wasted with that one), Cool Iris webpage previewer, FoxLingo (I like languages), and a couple other ones. The main point is I couldn't imagine going back to IE. Even Opera has some cool plugin widgets that I use all the time like for local weather and everything.