Fred's Notes from the Active Directory Best Practices from Robert Wakefield with NowMicro:
Backup of group policies via GPMC or script. Most GP admins do not backup group policy objects.
It's not a bad idea to backup directly from the GPMC
Use PowerShell to backup GPOs, this can be scheduled. Group policy backup via PS doesn't get links or security, etc. Only the object itself.
Use a central store to gather and distribute ADMX files.