Distribution for general purpose security
I'm looking for a good distribution for a somewhat beginner.
The main requirements is to have a distribution to learn more about Linux in general, and security technology in special. Special purpose distros such as Backtrack 2 is not an option, since the machine also will be used as my main machine.
I'm experienced in computers, but most of all my competence is now on the Microsoft platform (servers, Exchange and A.D), but need to learn Linux, very well.
I would highly appreciate recomandations for a good distro.