I've been meaning to document the set of firefox extensions I'm currently using, partly to share with others, partly so they're easy to find and install when I start using a new machine, and partly to track the way my usage changes over time. Here's the current list:
Flash Block - disable flash and shockwave content from running automatically, adding placeholders to allow running manually if desired (plus per-site whitelists, etc.)
AdBlock Plus - block ad images via a right-click menu option
Chris Pederick's Web Developer Toolbar - a fantastic collection of tools for web developers
Joe Hewitt's Firebug - the premiere firefox web debugging tool - its html and css inspection features are especially cool
Daniel Lindkvist's Add Bookmark Here extension, adding a menu item to bookmark toolbar dropdowns to add the current page directly in the right location
Zotero - a very interesting extension to help capture and organise research information, including webpages, notes, citations, and bibliographic information
Colorful Tabs - tabs + eye candy - mmmmm!
Chris Pederick's User Agent Switcher - for braindead websites that only think they need IE
ForecastFox - nice weather forecast widgets in your firefox status bar (and not just US-centric)
Greasemonkey User Scripts
RSS+Atom Feed Subscribe Button Generator - finds RSS or Atom feeds on a page and inserts floating feed subscription buttons
FindScripts - finds greasemonkey scripts for the site you are currently viewing, invoked via a hotkey
So what am I missing here?
Since this post, I've added the following to my must-have list:
Tony Murray's Print Hint - helps you find print stylesheets and/or printer-friendly versions of pages
the Style Sheet Chooser II extension, which extends firefox's standard alternate stylesheet selection functionality
The It's All Text extension, allowing textareas to be editing using the external editor of your choice.
The Live HTTP Headers plugin - invaluable for times when you need to see exactly what is going on between your browser and the server
Gareth Hunt's Modify Headers plugin, for setting arbitrary HTTP headers for web development
Sebastian Tschan's Autofill Forms extension - amazingly useful for autofilling forms quickly and efficiently