Useful Firefox Addons

del.icio.us toolar and tag button (from Yahoo) for handling bookmarks
It's all text - allowing the use of your own editor for text-boxes on web forms
Read it later - Helps you avoid wasting time on the reading an interesting looking headline (on popurls) right away. Instead ... save it for later.
Screengrab!
TinyURL
Chatzilla - IRC client

(I've seen a number of useful addons mentioned periodically at the Lifehacker blog (lifehacker.com) --Rhansen 01:37, 29 November 2007 (EST) )