Two words here: OFF SITE.

That wonderful SAN in your data center can burn to a crisp just like the rest of the building.  I have had too many clients involved in disasters to not have learned the lesson.  None were involved in 9-11 but that was a wakeup call too.

Three more words: TEST YOUR BACKUP.

Backups are no damn good if you can't restore them.  I recovered data from a client with a faulty tape system.  All the bytes were there, just not in the right files.   Days on end were spent trying to piece that back together.  I even ran across a tape system that, when verifying the backup only ensured that the tape was readable.  I asked the vendor if there was a way to compare the data on the tape to the data on the drive.  The respose was, "Why would you want to do that?"  We did not buy that system.  Guess why.

'Nuff preaching.