I love Firefox on it's own, but the other reason I love this browser, besides the obvious, are the extensions. I use many, but these are extensions I can no longer live without. These in my opinion are the best of the best.

Maxemum TV-Guide (MTVG) is a desktop TV-Guide that uses xml-files with tv-listings generated by the binaries from the XMLTV-project. I have setup ad used this application on Kunbutu Breezy, Dapper, and Edgy.

Maxemum TV-Guide is here

XMLTV-project is here 

I am not a big T.V. fan, but it makes it nice to look up my favorite genre or channels without all the other crap getting in the way. 

A comic book created totally with open source software.

Update, today Edgy updater told me Flash 9 was ready to be updated. It was already installed since I ran the deb package below. I installed via the updater to be compliant. I assume you will not need this package an longer as Kubuntu will most likely upgrade any version of Flash to version 9.  

Update, the latest release is out and deb package has been updated.

Flash 9 beta dep package for Debian/(K)Ubuntu

Installing Glest, which is a well done 3-D rpg game, on Kubuntu Edgy.