I have to admit I keep a lot of extensions installed in my browser, but most of them are disabled because I don't need them too often. If I need them, I just enable that extension an restart the browser. I also discovered that the more extensions you have enabled the longer it takes Firefox to load and the more memory it uses.
So here is my list of favorite Firefox extensions:
- All-In-One Sidebar: View dialog such as downloads, extensions, and more; view source of web page, or whole websites in the sidebar.
- Image Zoom: Gives you complete control of the size of most images displayed inside the browser.
- DeskCut: Adds the ability to create desktop shortcuts from the right-context menu.
- CopyURL+: Quickly copies the web site title, and/or selected text, plus the URL to the clipboard.
- Google Toolbar for Firefox: If you use any of Google services (such as: search, Blogger, Gmail, and more), this toolbar makes them quickly available to you. The toolbar even offers a spelling checker feature. (Here is a list of free Google Firefox extensions, some of which have already been incorporated into the new toolbar).
- Crash Recovery: Recovers all opened tabs and windows after a crash.
- IE Tab: Embedding Internet Explorer in tabs of Mozilla/Firefox.
- Tab Mix Plus: Enhances Firefox's tab browsing capabilities. It includes such features as duplicating tabs, controlling tab focus, tab clicking options, undo closed tabs and windows, plus much more. It also includes a full-featured session manager with crash recovery that can save and restore combinations of opened tabs and windows.
- Make Firefox Remember Passwords: This is not extension, but it's a bookmarklet that adds some good functionality.