As previously noted, my new lightweight favourite is Bodhi, which is Ubuntu-based but with the Enlightenment window manager. It is fast, very customizable and seems to have all the battery saving features that were incorporated into Ubuntu. That is not to say that CrunchBang isn't a good distro; it is. CB is also very customizable, though it requires more command line to do so (openbox doesn't have as many GUI controls as Gnome, KDE or Enlightenment). And the CB forums are among the best of any distro. I did try adding energy saving scripts to it, but never got the battery life success I achieved with Ubuntu and Bodhi.