Does anyone have any advice on the best way to backup about 50 Windows
2000 Desktop and Laptop clients with Netbackup DataCenter 3.4? 

We currently have a DLT tape library with 6 DLT 7000 tape drives. Two of
the drives are connected to NDMP hosts, so only four drives are
available for Windows backups. The drives are used each night between
12:00 AM and 9:00 AM for performing Server Backups. Also they are used
all day Monday and part of Tuesday for duplicating tapes to be sent
offsite. 

I'm thinking of backing up the Windows Clients to a Disk Storage Unit,
and then backing up the associated filesystem.