Debian

What I use for all of my server work. I could probably do okay with RHEL/CentOS these days, but Debian made understanding dependencies much easier, so it became my server distro of choice.

Guides Available

 * Debian Wheezy - Currently running on three servers, a detailed LEMP stack with a MySQL-backed Postfix+Dovecot solution.
 * Documentation for Squeeze and Lenny exists if there is interest, though it is not as thorough.