8 Essential Extension of Firefox

DownThemAll

This download manager lets you speed up, queue, and batch downloads from the Web based on your previously defined patterns.

Foxmarks Bookmark Synchronizer

Foxmarks synchs your bookmarks among different PCs and operating systems, making it perfect for getting your office and home bookmark libraries in harmony.

FoxyTunes

FoxyTunes can control any of over 30 media players (including iTunes, Musicmatch Jukebox, and Windows Media Player) straight from the browser window. Artist and track information, play controls, and a slider to adjust volume are presented discreetly in your browser.

Gmail Manager

This extension that lets you manage multiple Gmail accounts and receive new mail announcements as a pop-up on your status bar, eliminating the need to keep Gmail open in a separate window.

Googlepedia

Googlepedia shows you the most relevant Wikipedia article alongside your Google search results.

Reload Every

This extension allows you to program Firefox to refresh all open tabs, or one tab, after a set amount of time. It's especially useful for monitoring very active forums.

Session Manager

Session Manager lets you save the layout and addresses of all your tabs when you shut down Firefox, allowing you to keep that same layout when you open the browser up again.

Tree Style Tab

As the name suggests, this extension allows you to have a tree-style tab bar, like the folder-view tree that's used in Windows Explorer.