Migrating domain users with admin access on their systems ..

Hi,
I'm looking for a way to properly migrate domain users who have been members
or the local "Administrators" on their own systems to regular Users or Power
Users so that they can't install malware on their machines. For some reason
by default the %USERPROFILE% folder is owned by the "Administrators" group
instead of the actual user. What's the best way of handling this? Are
there any other "got ya's" when doing this?

Thank you!

J.