Ubuntu vs. Kubuntu - A Linux Lover’s Challenge
Both Ubuntu and Kubuntu are based on the same cannonical distribution and core. The only (and important) difference between them is the desktop environment offered with either option. Ubuntu comes with the Gnome desktop environment, whereas Kubuntu offers the KDE desktop.
KDE vs. Gnome
Many will say that the value of Gnome vs KDE is in their graphical presentation. KDE is a 3D highly graphical environment with much eye-candy objects. Gnome is a more basic, pleasant IMO, graphical implementation. It more resembles Windows XP in form and function.
In addition, KDE and Gnome each have different software packages that are specific to them. For example, KATE is a KDE text editor. Amarok is a KDE music player. Gnome has a whole set of tools specific to it as well. Most of these tools will work fine on either desktop. I have used Amarok on KDE and Gnome with no problems in either case.