Kubuntu is an Ubuntu-derived distribution. The Kubuntu CDs are made up of Ubuntu's base plus KDE. You can get exactly the same effect by installing Ubuntu and adding the KDE packages from the Ubuntu archives.

Kubuntu 8.04 now features two versions of the K Desktop Environment, a powerful graphical desktop environment which combines the ease of use, contemporary functionality, and outstanding graphical design with the technological superiority of the Kubuntu operating system. The stable release of KDE in Kubuntu 8.04 is version 3.5.9. The edgier release of KDE in Kubuntu 8.04 is version 4.0.3.