Looks like Microsoft will be offering up 7 versions of their next generation of Operating Systems. Its all about choice (or confusion if you ask me).
Microsoft plans two general Vista edition categories, which map closely to the two that exist today for Windows XP (XP Home Edition, which includes XP Starter, Home, and Media Center Editions, and XP Professional Edition, which includes XP Pro, Pro x64, and Tablet PC editions). Vista will feature two categories: Home and Business. In the Home category, Microsoft will create four product editions: Vista Starter Edition, Vista Home Basic Edition, Vista Home Premium Edition, and Vista Ultimate Edition (previously known as the “Uber” Edition). The Business category will feature three editions: Vista Small Business Edition, Vista Professional Edition, and Vista Enterprise Edition.
via Windows IT Pro