The six major versions of Windows Vista are detailed in

Windows Vista product version classification

In various Windows Vista versions, it can be divided into two categories, Home and Business, which correspond to the current versions of Windows XP. Currently XP is divided into: Windows XP Starter, Home, Media Center, Professional, Professional x64, and Tablet PC.

Home will be divided into:

Windows Starter 2007 (Beginner Version)

Windows Vista Home Basic (Primary Home Edition)[There is also Home Basic N for the European market. ]

Windows Vista Home Premium (Enhanced Home Edition)

Windows Vista Ultimate (Ultimate Edition) [Before this became a version of "Uber"]

Business has three Version:

Windows Vista Small Business (Small Business Edition)

Windows Vista Business (Business Edition) [formerly known as Professional Standard Edition, with Business N for European users]

Windows Vista Enterprise (Enterprise Edition) [Before becoming Professional Premium]

In other words, Winodws Vista is currently divided into 7 versions. If you count two N versions for the European market, that's nine. It's important to note that at present, all version names are just a code name. The names of these versions may change at any time before they are released. However, the division of these versions should not be changed within a week or two.

Figure Windows Vista product line

Second, Windows Vista version details

These news about each version comes from Microsoft's marketing department.