Here's a tip from my colleague Ed Wilson (a.k.a. The Scripting Guy at Microsoft) that shows you how to use Windows PowerShell to document optional Active Directory Domain Services features.
Question: How can you document which optional AD DS features are enabled?
Answer: Use the Get-ADOptionalFeature cmdlet from the ActiveDirectory RSAT module and choose everything. This command appears here.
Get-ADOptionalFeature -Filter *
Ed Wilson is the bestselling author of eight books about Windows Scripting, including Windows PowerShell 3.0 Step by Step, and Windows PowerShell 3.0 First Steps. He writes a daily blog about Windows PowerShell call Hey, Scripting Guy! that is hosted on the Microsoft TechNet Script Center; for more PowerTips check out the Hey, Scripting Guy! blog.