KDE

From the site:

"KDE or the K Desktop Environment, is a network transparent contemporary desktop environment for UNIX workstations. KDE seeks to fulfill the need for an easy to use desktop for UNIX workstations, similar to desktop environments found on Macintosh and Microsoft Windows operating systems. The UNIX operating system is according to us the best available today. When it comes to stability, scalability and openness UNIX has no competition. In fact UNIX has been the undisputed choice of information technology professionals for many years. The lack of an easy to use contemporary desktop environment, however, has prevented UNIX from finding its way onto desktops of typical computer users in offices and homes. UNIX today dominates the server market and is the preferred computing platform for computing professionals and scientists alike. The Internet, a household name traces its heritage to UNIX. Inspite of such ubiquitous creations from the UNIX community, average computer users still expect it to be difficult to use and often stay away. This fact is particularly unfortunate since a number of implementations of UNIX, all of which are of exceptional quality and stability (Debian GNU/Linux, FreeBSD, NetBSD etc.) are freely available of the Internet."