ArchLinux is a fast, technical linux distro made by Judd Vinet. It has a wonderful package management system (pacman) and is easier to configure through configuration files compared to other distros (because it does not have any GUI based configuration tools). ArchLinux embraces the KissPrinciple (Keep It Simple Stupid) but that does not mean you miss out on things like KDE; instead they clean up KDE so it has everything you can think of but not what you can't. Also, the automatic dependency solving is a great help. I would say this is the undoubtedly best Medium to Advanced Linux distro there is. Unfortunately, hardly anyone knows of it.