Knoppix is a Live CD and/or Live DVD.

Kunbuntu is primarily intended to be installed to hard disk. While Kubuntu does have a Live CD mode, I found the software available when running as a Live CD very limiting. Worse, I couldn't see any difference at all between the software that comes ready to run on the Live CD and the software available to run on the Live DVD! If anyone knows why this is, please explain it. I can't in good faith recommend Kubuntu as a Live Linux system.

There are many good Live Linux CD out there. The focus of this website is Knoppix, but we sometimes touch on some of the others, particularly the Knoppix derived ones. See this forum.

There are many good Linux distros out there intended for install on hard disk. Knoppix is not one of them. Ubuntu and Kubuntu are getting good word of mouth for having a lot of driver suopport built in, but in the end the user has to make the choice of which distro to use, there are many good distros, including Debian, on which both Knoppix and Ubuntu are based.