As with anything you should be backing up your Hyper-V machines.  I think that just goes without saying.  Backing up Hyper-V has gotten easier with the addition of VSS and Windows Server Backup (WSB).  WSB is a new feature in Windows Server 2008 that replaces the old NTBackup from days gone by.  It is not installed by default ...

Sysprep is a great tool, to create an image that can be pushed out to client machines. With Sysprep, you can install the OS and any applications, create the Sysprep image and then push it to other client or server machines. Within minutes you can have the other systems up and running with all the require applications, service packs and hotfixes ...