CrunchBang is only number 99 in the Distrowatch ranking but it has lot of dedicated users. CrunchBang is based on Ubuntu but it is designed to be more lightweight which of course can be seen in the default applications used by the distro. Ubuntu's GNOME has been replaced by much lighter and simpler Openbox. Desktop applications use GTK+. In addition, CrunchBang provides all the necessary multimedia codecs out of the box.
Even if CrunchBang has not been designed to be used on old computers, many users have reported it to be lightweight enough for older boxes. It certainly is worth a try if you want to have all the multimedia applications easily installed in an Ubuntu-like system running on reasonably recent hardware. But remember that the project does not guarantee anything at all:
CrunchBang Linux is not recommended for anyone needing a stable system or anyone who is not comfortable running into occasional, even frequent breakage. CrunchBang Linux could possibly make your computer go CRUNCH! BANG!
There is also a brand new CrunchEee edition which is certainly interesting if you are one of the happy owners of a new Eee PC. It is not yet finished but it is already available as a release candidate version. Another version of the distro is the CrunchBang Lite edition. The download links for the standard CrunchBang can be found here.