I don't disagree with a single thing posted here.
Check out mozy for backups btw, dirt cheap and it works well so far for me. I backup all my machines to one local drive and then back that drive up to Mozy. ~500Gb
Single drive, RAID 0, RAID 1 - Don't look at them as backups/or saftey at all. I bought a RAID 5 NAS that crapped on me several times. I've had servers running RAID 5 that I still lost data and ..... had to restore from a -back-.
RAID 0 is nice to increase space and if there is a bunch of data be moved to/from the drive or whatever it can help there. In general though, I would not stress it. I'd do the single drive and use the 160Gb drives a single drives for other crap. Just backup and backup your backups. (i.e.) mozy.
In my home now for everything I backup PCs to my NAS (RAID0), which backsup to a PC, which that then does an Internet backup to Mozy. I've lost way too much data in the past to not do this.
My '03 Sold.