Well you'll have to show me what Ubuntu has that Debian does not. Kubuntu, I suspect, is only named because it was originally sponsored by Canonical. Nothing more.
> Well you'll have to show me what Ubuntu has that Debian does not.
Ubuntu maintains a set of repositories for each version of Ubuntu, which (even when the same--by name--software is in Debian's official repositories, will often be different versions or otherwise different contents than Debian repos).
Kubuntu uses entirely software from the Ubuntu repos from the corresponding version number (e.g., Kubuntu 12.04 uses exactly the same set of repos as Ubuntu 12.04.) You can, in effect, switch from Kubuntu to Ubuntu, or vice versa, just using the apt package manager without changing the base repositories, just installing and removing the right packages from the ubuntu repos.
The difference between Kubuntu 12.04 and Ubuntu 12.04 is entirely in which packages, from the Ubuntu "precise" repositories are installed by default. The difference between either and any version of Debian is much greater.
The whole "unity or you have to call it 'Debian-based' instead of 'Ubuntu-based'" idea is nonsense.
Surely you're joking, right? For one, Ubuntu has a desktop and server version along with a LTS version and the repos are totally different. The filesystem layout is little different between the two. I'm sure there's more like init differences, differences in installation and configuration, kernels, and stuff in /etc, but I haven't used Ubuntu in quite some time.
