Microsoft has made the version of Windows 7 simpler compared to Windows Vista. Below are the editions:

Windows 7 Starter - this should have the basic features namely: new taskbar, standard Windows Media Player, Jump Lists, Backup and Restore, Action Center, Device Stage, Fax and Scan, a few games

Windows 7 Home Premium - the following features are missing in the starter edition but found on the home premium namely: Aero Glass & Background, Home Group creation, Media Center, Windows Touch, DVD playback and authoring, more games, Mobility Center

Windows 7 Professional - this has everything that the home premium has plus: Joining in Domains, advanced backup, Remote Desktop host, EFS, Offline Folders

Windows 7 Enterprise - this has everything that the professional edition has plus: BitLocker To Go, BitLocker, AppLocker, Direct Access, Branche Cache, MUI language packs, boot from VHD