Security and Penetration Testing Distributions

BackTrack - Linux security distribution
Matriux - Debian based security distro
nUbuntu -
Samurai - Web Testing Framework
OWASP Live CD project - Web application security distro
Pentoo - Security-focused livecd based on Gentoo
Katana - Portable multi-boot security suite
KON-BOOT - Change contents of a linux/windows kernel while booting
Linux from scratch! - Building your own custom Linux system
SUMO Linux -
Pentesting packages for ubuntu - A script to configure Ubuntu box for pentesting
BackBox Linux - Flexible penetration testing distribution