Ubuntu is the top Linux distribution world wide. It has enabled less technically sophisticated Linux users to easily run the open source software on their desktops for the first time. Ubuntu uses GNOME as it's preferred desktop solution, and this project has recently announced a major overhaul which is equivalent to a jump from XP to Windows 7.
Many people prefer Linux because with a little effort it is infinitely customizable. Enterprising hackers have packaged their own customizations into distributions which each have a distinctive flavor, including Linux Mint, Ubuntu, Crunchbang, E-Live, Debian, Fedora, Red Hat, and SUSE. The new version of GNOME, called GNOME 3.0, is currently supported by the openSUSE and Fedora projects. It has been under construction for five years, and there are major changes to the look and feel of the system which has been designed with the cloud in mind.