Highly functional, with all the applets and other toys people are used to, but not bogged down with too much useless bloat, making it much quicker than Gnome and KDE. Although not heavy on eye candy, it can be easily configured to look quite nice.
One of the best desktop environment systems for beginners and intermediates. The GUI doesn't hide much options from the user and the user can modfiy it using the GUI itself.
Xubuntu is a personal favorite.