Here is page of operation systems statistics
for years 2009 and 2010. There are six commonly used operations systems: WinXp, WinVista, Win7, Linux, Win2000, Win2003.
Win2000, Win2003 going to die, WinXP stay more popular, but all new computers is setuped with Vista, that is why Vista going to be more usable than XP in os statistics
Win7 is the nevest Windows distributive, and looking pretty. Windows 7 was released to manufacturing on 22/07/2009, and reached general retail availability on 22/10/2009, less than three years after the release of its predecessor, Windows Vista.
Linux have lots of distributives, the most popular are Ubuntu, Debian, SuSe, Mandriva, Fedora. As you can see, linux going to be more popular. Linux and biggest part of software is free - it's a big plus for using.
Linux is a generic term referring to Unix-like computer operating systems based on the Linux kernel. Their development is an examples of free and open source software collaboration; typically all the underlying source code can be used, freely modified, and redistributed, for non-commercially and commercially with using GNU General Public License.
This os type become more and more usable for beginners. OS statistics
showing that platforms similar to linux are the best solution for internet server.