Based on my experiences from Ubuntu, Kubuntu and PCLinuxOS, I've to go with Gnome. KDE on PCLOS is OK, but the one on Kubuntu, whether it is 3.5 or 4 or whatever, has almost always been a bad experience for me. Varies from being slow to crashing to just being annoying to use. The latest Kubuntu looked GREAT. But I just prefer Gnome for it's simplicity and working well for me.