I want to turn one of my Pis into a dedicated backup server. Setting it up isn't a problem, but I'm not really sure what to use in terms of physical storage media. A standard external HDD is probably the easiest (and cheapest) way to go but I feel like having a disk spinning 24/7 is going to lead to failure unless I shell out for an industrial unit. Solid state technology isn't exactly foolproof either though, at the moment I'm ftping documents to a USB stick stuck in the side of the PI, but they always seem to fail on me at very inconvenient times.
Am I being paranoid? Should I just spend the extra and set a RAID up? What do you guys use? For what it's worth I only need about 200GB of spac

