split between Xubuntu and Lubuntu
The LXDE Lubuntu desktop runs extremely well on low RAM hardware such as my old netbook. I tend to prefer Xubuntu on better provisioned desktops. Haven't looked at Gnome or KDE for a few years since their developers seemed to lose the plot, though that may have changed since. The great thing about having choice in this environment is that all the Gnome/KDE whatever oriented applications seem to install and run fine on all the desktop manager options, so changing desktop managers doesn't require you to change your applications.