Which Linux to use is a philosophical question.
1. Are you going to raise my Linux server to 1C, i.e., X s(graphics, etc.) You do not need.
2. Basic requirements for server stability and speed (not going to touch the "high" theme, when the question "what Linux to choose")
Items you can add to infinity, but while I think that's enough.
take a stable distribution focused on server-side work. With a clean RHEL and Suse are troubles with the licensing, respectively, remains - Centos and Debian