James,
The backup is a full information store backup, with Veritas Backup Exec 9.1 (with the Exchange Agent) and an U320 HP Ultrium 960 drive on an SmartArray 5300 controller. I've been able to do some housecleaning and got the databases down in space on that server. The information store backs up about 28GB in 10 minutes now.
Set Detail Information - Backup \\Server\Microsoft Information Store\First Storage Group
Set type : Backup
Set status : Completed
Set description : Friday n1
Resource name : \\server\Microsoft Information Store\First Storage Group
Agent used : Yes
Advanced Open File Option used : No
Image used : No
Start time : Saturday, December 17, 2005 6:59:52 AM
End time : Saturday, December 17, 2005 7:09:36 AM
Byte count : 28,644,647,726 bytes
Rate : 2,806.00 MB/Min