Firefox Ad-ons

This is a list of Firefox Ad-ons I use. I've broken them down into extensions I use when developing a site and ones I use just to make life easier on the web.

Development

Web Developer - Adds a menu and a toolbar with various web developer tools.
HTML Validator - The number of errors of a HTML page is seen on the form of an icon in the status bar when browsing. The details of the errors are seen when looking the HTML source of the page.
LinkChecker - Checks for broken links on a web page.
FireBug - FireBug lets you explore the far corners of the DOM by keyboard or mouse. All of the tools you need to poke, prod, and monitor your JavaScript, CSS, HTML and Ajax are brought together into one seamless experience, including a debugger, an error console, command line, and a variety of fun inspectors. Requires the DOM Inspector to be installed with Firefox to work with CSS.This plugin may also cause forms to not work correctly. You may have to disable this extension at times.
Palette Grabber - Creates a color palette for Photoshop, Paint Shop Pro, GIMP, or Flash based on the current page.

Useful for everyday use

Foxmarks Bookmarks Synchronizer for Firefox : "The Foxmarks Bookmark Synchronizer automatically synchronizes your bookmarks between two or more computers running Firefox. It also lets you access your bookmarks from any computer anytime via my.foxmarks.com." — I still backup my bookmarks every once in a while since it seems their server gets slow every once in a while. If they come out with an update then it is usually a good time to back up your bookmarks then.
Flashblock - Never be annoyed by a Flash animation again! Blocks Flash so it won't get in your way, but if you want to see it, just click on it. See NoScript note.
NoScript - Block Java and JavaScripts from websites. You can allow trusted sites. Some sites place their Flash with JavaScript, so this script may cancel Flashblock.
Tab Control - Take control of your tabs! Purposely lightweight extension with the following features: * (Optionally) Position new tabs to the right of the current tab * (Optionally) Switch to the left tab when closing the current tab * (Optionally) Protect window from closing with close-tab hotkey * Set some or all javascript window.opened windows to redirect into tabs * Specify the min and max width for tabs
MinimizeToTray - Minimizes Mozilla windows into the system tray. Also includes a right clickable tray icon menu to further load only the windows you want visible.
IE View Lite - Vew websites in Firefox through the Internet Explorer rendering engine. No need to switch to IE for websites that don't work i Firefox.
Full Fullscreen - Hides remaining toolbars that the normal fullscreen functionality does not. Hiding the tab bar, as well as starting up on fullscreen, are configurable from the settings dialog.