Ext3 and RAID: silent data killers?

This is a good way to look at it. Starting with a near-CDP tool such as rsnapshot is a good approach to snapshots, backing up data as frequently as every hour with low overhead, through rsync with multi-version support through hard links between snapshots. Then if the overhead of a scan every hour is too much, or you need very fast recovery from a disk fault, add RAID as well.