Next major version of Microsoft Windows after Vista

Windows 7 (formerly known as Blackcomb and Vienna) is the working name for the next major version of Microsoft Windows as the successor of Windows Vista.

Microsoft has announced that it is "scoping Windows 7 development to a three-year timeframe", and that "the specific release date will ultimately be determined by meeting the quality bar."

The client versions of Windows 7 will ship in both 32-bit and 64-bit versions.

A server variant, codenamed Windows Server 7, is also under development.

en.wikipedia.org/wiki/Windows_7

Live link: http://en.wikipedia.org/wiki/Windows_7

I would suggest staying on Windows XP because of software incompatibility for Windows Vista.