35 Absolutely Useful Firefox Plugins For Web Designers And Developers

Good, although I would add:

  1. Web Developer by Chris Pederick – Absolutely essential for web developers.

  2. ColorZilla by Alex Sirota – Good for UI mockups instead of having to worry about remembering hexadecimal values for colors, this does the hard work for you.

  3. DOM Inspector by Shawn Wilsher – Simple, but does the job.

In addition, although not an add-on, I would replace FireFTP with Cyberduck. After only 1 summer of using it, I would gladly pay for a piece of software that is as polished and full-featured as this.