Kubuntu

http://kubuntu.org

Kubuntu is a Linux distribution, a derivative of Ubuntu, with KDE as its default desktop. With a bit of configuration, it can be used by Windows or Macintosh users with very little training. It has a large community providing help to people who like to customize their operating system.

http://gnu.org Linux with

http://debian.org package system and core work

with some good direction from http://ubuntu.com which helps direct development of "Linux for Human Beings"

and http://kde.org which is an actual usable shell ( user interaction layer)

Since the default desktop on Ubuntu, Disjointity, (They call it Unity) is unfriendly and onerous, very few people recommend using Ubuntu. We would rather use kubuntu, and have used xubuntu and lubuntu with some people preferring Mint