1.) Ubuntu Studio : a linux distro made for people who love creating Audio, Graphics, Video, Photography and Publishing.

2.) Scientific Linux : a Linux release put together by Fermilab, CERN, and various other labs and universities around the world. Its primary purpose is to reduce duplicated effort of the labs, and to have a common install base for the various experimenters.
3.) CnC Linux : a software system for computer control of machines such as milling machines, lathes, plasma cutters, cutting machines, robots, hexapods, etc.
4.) General purpose linux : Most notable here is Ubuntu which is very easy to install, has its own app center and has steam supported. It's a good platform also for gaming.

5.)If you are an experienced linux user and you want something more challenging then you can go to Arch-Linux and Gentoo. Both of them are minimal installations from which will provide you a minimal base system and you from a command line you gonna give linux the shape you want. You will chose the login manager, the desktop enviroment, the drivers. I would suggest Arch linux because the installation is very much easier from Gentoo and because of its awesome package manager the Pacman which seriously with one just command can update your entire system packages.
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