1. Reference Desk
Reference Desk is good for students or anyone who needs to research information. It installs DeeperWeb, which navigates through Google search results using tag-cloud techniques; SimilarWeb for finding related sites; the Converter unit, time zone and currency converter; the Merriam-Webster dictionary; the Wired-Marker highlighter; ScrapBook for saving and organising sites; Reframe It for connecting and sharing your thoughts online; and Read It Later for saving sites for browsing another time.
2. Web Developer's Toolbox
Web Developer's Toolbox will help speed up your development process with extensions for troubleshooting, editing and debugging web projects.
3. Traveler's Pack
Traveler's Pack is a great tool for anyone on the move. You can plan, book and document trips. This collection includes BabelFish Instant Translation; FoxClocks for the time wherever you are; Flagfox for displaying the national flag of the site you are on; the Deep Web Search Engine, which shares sites through Samucaya; the ScribeFire Blog Editor for easier blogging; the Lonely Planet travel guides; Fotofox for dragging, dropping, arranging and uploading pictures without interrupting your browsing; the Minimap Sidebar for maps and mapping tools; and Yapta for shopping comparisons.
4. IE Tab
IE Tab will embed Internet Explorer tabs within Firefox. With this extension, you can take advantage of the power of two browsers in one window. But this extension is not available for Linux.
5. Power Twitter
Power Twitter adds features to the Twitter web interface, such as inline YouTube and other sites, link-to-page-title translation, specific user-search scoping, status history on mouseover and link shrinking.
6. WOT Safe Browsing Tool
The WOT Safe Browsing Tool will let you know if a website is safe to browse. Using a traffic-light rating system, it shows you which sites are safe, questionable or unsafe.
7. NewEgg Toolbar
The NewEgg Toolbar allows you to navigate and shop on NewEgg. With this extension, you can browse bestsellers, popular gifts and more. You can also use it to sign in and to check order, status, history and wishlists.
8. PDF Download
PDF Download is a handy PDF-centric tool that allows you to take whatever action you like with a PDF document. View PDF docs as HTML in Firefox or use the web-to-PDF toolbar to share pages as high-quality PDF files.
Monkeysphere offers an alternative to the standard, centralised certificate authority scheme. With Monkeysphere, you can validate HTTPS-enabled websites using the OpenPGP Web of Trust instead of depending on often-unreliable certificate authorities.
What are your favourite extensions?
Have you come across an extension you can't work without? If so, share it with us.