The otherday I had to redo my hard drive so I decided that it was a good time try out Firefox (and Thunderbird for E-Mail). Anyway I notice there are a lot of addons for both Firefox and Thunderbird. So far all I gotten is the "N-Scape1" theme (I'm an old Netscape user) and "DownThemAll!" (a good download manger is needed here in Dial-Up hell).
I want to know which addons you think are must haves and which addons should be avoided like the plague.