• Windows PowerShell Cmdlets for Group Policy: Ability to manage Group Policy from the Windows PowerShell™ command line and to run PowerShell scripts during logon and startup
• Group Policy Preferences: Additional types of preference items
• Starter Group Policy Objects: Improvements to Starter GPOs
• Administrative Template Functionality: Improved user interface
• Administrative Template Settings: New and changed policy settings

Group Policy Preferences are a heap of new Group Policy settings that were released with Windows Server 2008 that allows IT administrators to pretty much do anything they want to configured computers in an corporate environment. Preferences only require a Windows 2000 Active Directory and they need to be managed from a minimum of Windows Vista/2008 however they can be applied to Windows XP Service Pack 2 (or greater) workstations.

• Active Directory Recycle Bin
• Active Directory module for Windows PowerShell and Windows PowerShell™ cmdlets
• Active Directory Administrative Center
• Active Directory Best Practices Analyzer
• Active Directory Web Services
• Authentication mechanism assurance
• Offline domain join
• Managed Service Accounts
• Active Directory Management Pack
• Bridgehead Server Selection

Active Directory Recycle Bin helps minimize directory service downtime by enhancing your ability to preserve and restore accidentally deleted Active Directory objects without restoring Active Directory data from backups. By default, Active Directory Recycle Bin in Windows Server 2008 R2 is disabled. To enable Active Directory Recycle Bin, your environment must meet the requirements to completed scenario.

The tombstone lifetime in an Active Directory forest determines how long a deleted object - aka a 'tombstone' - is retained in Active Directory. The tombstone lifetime is determined by the value of the tombstone Lifetime attribute on the Directory Service object in the configuration directory partition.
Tombstone Lifetime assists in removing objects from replicated servers and preventing restores from reintroducing a deleted object. Actually when an object is deleted from Active Directory, it is not physically removed from the Active Directory for some days. Instead, the Active Directory sets the 'isDeleted' attribute of the deleted object to TRUE and move it to a special container called 'Tombstone'.