IRsoft - Software and more by Ingmar Runge

This is a list of some cool Firefox Extensions. All Extensions listed here are FF 1.5 compatible.

Greasemonkey

Makes it possible to modify every web page with custom JavaScrips. A must-have!
A huge number of user scripts is available at userscripts.org and I also wrote some.

Adblock Plus

Extended version of the popular Adblock extension. My filter list

HTML Validator

Based on the W3C tool Tidy, this extension shows information about the "cleanness" of a web page's source code. But please keep in mind that this is not a real HTML Validator, pages are often accepted with "0 errors / 0 warnings" by this extensions but nevertheless fail in the W3C Validator.

CuteMenus - Crystal SVG

Adds nice icons to all of Firefox's menus.

SessionSaver

Saves open windows and tabs and restores them after a browser restart. May slow down Firefox a bit with a huge number of open tabs.

Tabbrowser Preferences

Pushes Firefox's great tabbed browsing features even further. An absolute must-have extension!

DownThemAll!

Makes it possible to download all images or all linked images or all linked archive files etc. from a page. Very useful. :>

Web Developer

Adds a lot of great features such as "Disable/Enable All Stylesheets" with shortcut Ctrl+Shift+S to Firefox.

View Cookies

Adds a new tab page to the Page Info dialog showing all cookies of the current page.

Stop-or-Reload Button

Saves toolbar space by combining the Stop and the Reload button.

LiveHTTPHeaders

Adds a new tab page to the Page Info dialog showing the raw HTTP request and response headers.