Windows 7 will come in 6 different editions:
a) Windows 7 Starter Edition
This edition has limited functionality, e.g. no Windows Aero theme and maximum 3 active applications, and will be pre-installed on computers like netbooks.
b) Windows 7 Home Basic Edition
Only available in emerging markets like Brazil, China, India, Indonesia, Mexico and Thailand. Users can run an unlimited number of applications but certain Aero features are excluded.
c) Windows 7 Home Premium Edition
Aimed at the home market, most users will be using this edition.
d) Windows 7 Professional Edition
Aimed at enthusiasts and small business users, this edition includes all the features of Home Premium and more advanced features like participation in a Windows Server Domain, serving as a Remote Desktop, Encryption File System and Presentation Mode.
e) Windows 7 Enterprise Edition
This edition is for the enterprise market and will only be sold through volume licensing with companies which have Software Assurance contract with Microsoft. Includes Multi-Lingual User Interface, BitLocker Drive Encryption and Unix support.
f) Windows 7 Ultimate Edition
Contains the same features as the Enterprise Edition but made available to individual end-users. Unlike Windows Vista, it will not include Windows Ultimate Extras.
Among all these editions, only the Windows 7 Home Premium and Professional editions will be available through retail. However, they will include ALL the features of Windows 7 and users only need to buy an upgrade through the Windows Anytime Upgrade program to unlock these features.
All editions will also include both 32-bit and 64-bit support, except the Starter Edition.
Credit: Windows 7 cover art by lee13d @ deviantart.com