Windows 7 Home Premium is the standard consumer SKU, providing full functionality on the latest hardware, easy way to connect, and a visually rich environment.  Home Premium includes these additional features:

• Aero Glass & advanced windows navigation
• Create a HomeGroup for easy networking and sharing across all your PCs and devices
• Windows Media Center and media streaming, including Play To, and improved media format support
• Multi-touch and improved handwriting recognition

Windows 7 Professional is the business-focused SKU for small and lower mid-market companies and users who have networking, backup, and security needs and multiple PCs or server. Professional includes these additional features:

• Domain Join
• Group Policy Controls
• Encrypting File System
• Advanced Backup
• Remote Desktop Host
• Windows Mobility Center: Presentation Mode*
  *Only on notebooks

Windows 7 Ultimate is the no-compromise consumer SKU for those who want all Windows features, including business. Enterprise is the business-focused SKU for managed environments, advanced data protection, networking, and security needs - available through SA agreement.  Ultimate and Enterprise include these additional features*:

• Direct Access
• BranchCache
• Enterprise Search Scopes
• BitLocker™ & BitLocker™ To Go
• Applocker™
• Multi-lingual User Interface
• Network Boot License
• VDI and RDP Enhancements

*Some features require Windows Server 2008 R2