• Firebug
• Add N Edit Cookies
• CSS Viewer
• Tamperdata – tamper with HTTP requests
• Web developer
• Load time analyzer
• View source chart

• Resizable form fields
• NoSquint
• It's All Text – launch a better editor for textareas

• Better GMail
• Better GCal
• Better Google Reader
• Google Calendar quick-add
• Google Notebook

• AdSense Preview

• Better Flickr

• Deepest Sender – blog posting client (incl. LJ)

• Auto copy – select copies to clipboard, like in X

• Adblock Plus
  • Disable snap.com previews permanently
• Pearl Crescent Page Saver
• SearchStatus – real-time Google PageRank and Alexa stats
• Tab mix plus
• FoxClocks
• Operator plugin (microformats)

• post to del.icio.us
• Add to Google Reader
• Mooch This (for http://bookmooch.com)
• Track co.mments
• Pluck It! (convert websites to Plucker .pdb format)
• Library lookup (for public library catalogues)

Add these bookmarks to quickly perform searches. Go to Bookmarks > Manage Bookmarks… > New Bookmark…

Google Search

• Location: http://www.google.com/search?q=%s
• Keyword: g

Wikipedia Search

• location: http://en.wikipedia.org/wiki/%s
• Keyword: w