By far my favourite desktop environment. Totally customisable, amazing graphics and so slick. Some people would say I'm biased! but when you try it out I doubt you will disagree with me.
I use e17 which is still in heavy development and thus not always as reliable as I would like. When it is finally released it is going to be a desktop environment which beats all competition. At the moment I do fall out with it quite a lot. Mainly because it is unstable unless you have the most recent edition, and frequently when I update I lose all my nicely set up config files. Roll on the e17 guys agreeing and sticking with a final underlying structure and heading towards a release date.
The best part about Enlightenment is the eSheep . This is a module which I wrote with an animated sheep which wanders around on your desktop.
ctrl + alt + end restarts enlightenment (hold down all three at once)