All Vista World

Windows Vista : Wiki Definition

Its interesting that the wiki gives a disclaimer on its information about Vista :

This article or section contains information about scheduled or expected future product(s).
It is likely to contain information of a speculative nature and the content may change dramatically as the product release approaches and more information becomes available.

This is what it has to say anyway :

Windows Vista, abbreviated WinVI, is Microsoft’s next version of its Windows operating system, succeeding to Windows XP. It was previously known by its codename Longhorn (see the other Microsoft codenames). The name “Vista” was unveiled on July 22, 2005. Longhorn Server, the successor of Windows Server 2003, is yet to be named. Windows Vista will carry the version number 6.0 (Windows 2000, Windows XP and Windows Server 2003 being Windows NT versions 5.0, 5.1 and 5.2, respectively). The scheduled release date for Windows Vista is December 7, 2006.

Windows Vista has several planned new features such as an entirely new user-interface called Aero, improved searching technology dubbed Search, and an XML specification designed for document formats and similar in many ways to Adobe’s PDF entitled XPS. Windows Vista also has an entirely new development API, WinFX, along with several other key technologies. In addition, current speculation points to several different editions of Windows Vista being released, including starter, home, and professional editions. The new operating system had several previously scheduled features that are currently not planned to go into the operating system such as WinFS and the new command shell MSH. System requirements of the new software are also higher than previous versions of Windows.

You can read the full wiki description here