In a similar vein to the post on my favorite freeware programs on Windows, here I'll collect my favorite Firefox addons.
- Adblock Plus - great for blocking flash ads
- ChatZilla - my IRC client of choice. No need to install a separate program - this plugin is great
- Download statusbar - a convenient way to track multiple downloads on the status bar in a compact manner
- Firebug - an amazing tool for web development and scraping
- gTranslate - translate words and phrases by selecting and right-clicking them, using Google Translate as the backend
- keyconfig - configure keyboard shortcuts (http://mozilla.dorando.at/keyconfig.xpi)
- Link Alert - a useful little plugin that changes the mouse cursor according to the linked file type when you hover over a link
- Pocket - wrote about it here
- Uppity - allows you to easily navigate one or more levels up on a URL
- Xmarks - annoys me occasionally, but still the best bookmark synchronizer. Essential if you use several computers on a regular basis
- YouTube to MP3 - pull the sound from YouTube videos into MP3s