Also remember there is Kubuntu aswell...
both Ubuntu and Kubuntu are nice..
I don't want to start a Window Manager war but..
KDE imho, is a bit more intuitive than Gnome.
Plus you get alot of slick KDE gui's for almost every application that's worth it... And to streamline the
Gui even more the GTK -> QT skinning engine is not bad
at all... It's not quite a rush yet, but it will be some day

It is a hawk on your computer resources though...
Untill KDE4 is out that is

Just my two cents on this...