If I were you, I'd skip RAID entirely -- it's generally overkill for our purposes and with cheaper, consumer-grade RAID I (and others) have experienced problems re-building the array when it fails (though in this regard RAID1 is safer than RAID3 or 5). If I were you, I'd simply get a couple drives and use SyncToy or some such to schedule automatic, periodic backups. (I do mine nightly.) Then keep one drive off-site, as planned, and refresh it regularly.