One common task when deploying enterprise machines is to add your desktop administrators to the local Administrators security group. You can do this with a task sequence property.
To add users or groups to the local Administrators group list them sequentially in your customsettings.ini like in this example:
Administrators001=SCRIPTIMUSDOMAIN\Desktop Admins Administrators002=SCRIPTIMUSDOMAIN\Helpdesk Admins
To add users to the Power Users group use this example:
PowerUsers001=SCRIPTIMUSDOMAIN\Scriptimus Prime PowerUsers002=SCRIPTIMUSDOMAIN\AndrewBarnes
As usual, these are propertys so you can use them in the database or as task sequence variables.