To go along with my previous post on deploying Windows via MDT 2010, here is a list of the “default” keys that Windows uses when you choose not to enter a product key during setup.  These keys of course will not activate, but you can enter them into your task sequences when you are prompted for a product key to use.  This will make your setup more unattended.

Update: If you want the default VL/KMS activation keys for Windows Vista through Windows Server 2012R2, they can be found here.