I'm using Gnome, more specifically I did:
so I got less packages to install and compile and then just add any extra that I want rather than emerging a full gnome desktop environment.
I prefer the look'n'feel of Gnome to KDE, nicer window decorations, very simple interface very promising future (the same looks true of KDE too, mind). Very easy to use & set up too - it's also fun to try it with xgl if you're so inclined
Before that I was mainly using e17 with nautilus as my graphical file manager. The desktop modules that are native to e17 integrate seamlessly into the desktop - much better than gdesklets or adesklets or superkaramba.