If it is always the same OS that is being installed slip-streaming the installation with the latest SP and fixes is the best way to go IMO. The problem with WUS and things like that is that the system will be on the network an unprotected until you tell WUS to go an update it. On slow links, the download part can still cause issues.

This is the best answer IMO. http://support.microsoft.com/default...b;en-us;828930