I'm experimenting with xmonad, which I installed from the Ubuntu Software Centre on Ubuntu 12.10. It looks cool, but when I invoke it (using
xmonad --replace from the command line) my title bars disappear and my keyboard stops working. At all. The terminal stops working, the keystrokes I've seen in online "getting started" guides are ignored, and the only way for me to actually power the system off is to hit the reset button or ssh in from my phone.
Ironically, my mouse still works.
One guide I saw suggested replacing the default window environment with xmonad, but I'm afraid of rendering my system completely inoperable if I do that.