I always try to keep the # of add-ons loaded on my Firefox at a minimum. In my many years of being in web development I have found that there are at least 3 essential add-ons that any serious web developer must have.
- Firebug – Live tracing and debugging for HTML, CSS, and JavaScript.
- Pearl Crescent Page Saver – Save an image of a web page to a file.
- Web Developer – Adds a menu and a toolbar with various web developer tools.
Snap Links – Opens multiple links contained in a selected area in new tabs. Get the Firefox 3 compatible version.