I think he already has SBS 2003 installed. 
I recognise that, but, I don't know if you noticed that he said he's now starting to migrate from a Win XP peer LAN.
SBS2003's built-in backup is a pain in the butt to use - and if you don't use it the built-in reports will keep nagging you about your backups, even if you have another backup system in place.
My backups are done using the DNS-323's built-in backup scheduler, which does not allow for incremental backups, so I'm doing a full backup every time, it may be slow as disks go, but it is significantly quicker than the tape that was there before, so I'm a happy camper.