StripPerms.exe will take ownership of all files on a drive or in a folder recursively, and then set the permissions to full access.
This is particularly useful when you are pulling a hard drive out of a dead laptop and putting it into an external enclosure for a customer.
StripPerms is for Windows 7/8 only and must be run with administrator permissions.

Update 8.28.2013 - StripPerms (v1.01) now supports directories instead of just drives. If you wish to do an entire drive simply select the root of the drive.

Update 12.27.2013 - StripPerms (v1.02) now does not follow symlinks, but treats them as regular files.