Debian
The Debian Project is an association of individuals who have made common cause to create a free operating system. This operating system is called Debian.
VS
Tails
The Amnesic Incognito Live System (Tails) is a Debian-based live DVD/USB with the goal of providing complete Internet anonymity for the user. The product ships with several Internet applications, including web browser, IRC client, mail client and instant messenger, all pre-configured with security in mind and with all traffic anonymised.