3. KNOPPIX 6.7.1

Now at No. 25 on the DistroWatch ranking list, was recently updated to version 6.7.1. The popular Debian-based live CD and DVD features the LXDE desktop. New additions in this latest release include an update from Debian "Squeeze"; Linux kernel 3.0.4 and X.Org Server 1.11; experimental free Nouveau graphics modules supporting Nvidia cards; LibreOffice 3.4.3, replacing OpenOffice.org; Chromium 13.0.782.220 and Firefox 6.0.2 web browsers; and eViacam, a program for controlling the mouse by moving your head using the webcam.

4. Scientific Linux 5.7

Targeting academic environments, 5.7 is a free, enterprise-class distribution built from source packages for Red Hat Enterprise Linux 5.7. New in this latest release are Alpine 2.02, a tool for reading, sending, and managing electronic messages; a stackable unification file system; gnuplot 4.2.6; Intel wireless firmware (ucode) Intel wireless; R 2.13.1, a language and environment for statistical computing and graphics; updated kernel modules for the XFS journaling file system; and updated kernel modules for OpenAFS and NDISwrapper.

5. CentOS 5.7