OpenMandriva Lx is an exciting free Desktop Operating System which aims to stimulate and interest first time and advanced users alike. It has the breadth and depth of an advanced system but is designed to be simple and straightforward in use.
Stable and extremely fast!
Best OS there is at the moment -- if only we had enough time to rewrite drakx in C++/Qt.
One of the best KDE-based distributions og GNU/Linux