It is being predicted that Microsoft will ship their new product Windows 7 in six different flavours. The provision for upgrading to the new version from older ones is still available but only after paying a license migration fee, which I suppose will be equivalent to the price of the DVD box set of the version of Windows 7 you are ordering. Now let us have some insight on each of these six different flavours of Windows 7.
Starter Edition: Mainly aimed at netbook users and emerging economies. It has limitations like users will be able to run only three applications at a time.With such restrictions in place I feel that MS is actually allowing Open Source OS to capitalize this Netwbook market.
Home Basic and Premium: These editions started with the oncoming of Windows Vista, prior to which we used to have only a Home edition. The Home Basic Edition and the Premium edition differ only on the grounds of eyecandy (like Aero Glass UI and the advanced window navigation) and the advanced touchscreen implementations which are available only in the Premium Home editions
Professional: This edition showcases mainly the security and networking features like encryption, advanced network backup and joining managed networks with Domain Join.
Enterprise and Ultimate Editions: Whether you're a home user or a business, the Enterprise and Ultimate editions will not differ much and will incorporate much advanced features like bitLocker data protection for internal and external drives, DirectAccess for corporate networking and will lock unauthorized software from running with AppLocker. More or less we feel many of these features have already been present on various Linux systems since long!