Stephan Spencer published a nice list of his favorite plugins and extensions that he uses with Firefox. If you are a SEO, Webmaster, or just a regular Internet user, you’re just missing out if you’re not using Firefox yet. It’s still by far the most robust browser out there and the number of extensions that make your life easier is just awesome.

There’s just one extension that I would add to Stephan’s list: SEOpen, a tool which allows you to get any SEO related information with just one click, ie. Yahoo! Backlinks, number of pages indexed in Google, and more.