There are people who believe that KDE 3 was the perfect desktop. They forked it when KDE 4 was released (initial KDE 4 releases were really rough), called it the Trinity Desktop Environment (TDE). I actually really like modern Gnome but every once in a while I try out TDE and it does give me a nice cozy feeling, like looking at old album photos.

I have a friend who refuses to use anything other than CDE and still manages to compile and run it on modern Linux distros.