I've been using Firefox as my primary browser for several years now. Up until a few days ago my repertoire of installed Firefox extensions consisted of Flash and Acrobat.

When I happened across an article spot-lighting several Firefox extensions on computerworld.com, I decided to give them a try.

Here are my top 7 favorites from the computerworld list:

1. Google Browser Sync enables me to have the same bookmark list at work that I do at home, and synchronizes my cookies so that I don't have to remember so many obscure passwords for rarely visited web sites.
   
   
2. Session Manager remembers a collection of open windows. It's sort of like being able to bookmark a session. This is very convenient as I usually have three or four firefox tabs always open (my mail, the news, etc.) and Session Manager remembers this configuration each time I start up FireFox.
   
   
3. IE Tab is helpful for those sites that only support Internet Explorer. Using IE Tab you can easily view such sites without leaving FireFox. It's also helpful if you want to test your HTML/Javascript against both FireFox and IE.
   
   
4. I like IE's built-in FTP client but hate having to leave FireFox to use it. Now, with FireFTP I no longer need to use IE's FTP. FireFTP is a full-featured FTP client that runs in a browser session.
   
   
5. One of the reasons that I like FireFox is the extra information that I see in the Error Console when developing Javascript. Firebug increases the amount of debug information available to the developer and makes it visible in a window at the bottom of the screen. This is great as I've always found keeping track of the seperate Error Console window a bit of a hassle.
   
   
6. Do you ever need to match a color displayed on a web page? For example when you're modifying an existing site and need to keep the theme intact? In the past my approach had been to take a screen snapshot then use Photoshop's eyedropper tool. ColorZilla makes this *so* much easier. Now I just click on the ColorZilla icon at in the Firefox tray area and then hover over the color I want to match.
   
   
7. Also useful is MeasureIt which allows you to easily measure any area on screen to determine the height and width in pixels.