One of the steps towards preserving your data throughout the ages is... storing it. As it happens, one of the Maxtor disks plugged into my main NSLU2 has started making clacking noises (never a good sign), so I'm now looking to replace it.
The disk in itself is perfectly replaceable - it's the one the NSLU2 boots from and runs the DAAP server, and it holds my MP3 (which I can always re-rip), a complete archive of my photos (which are replicated on my iMac and backed up on a quarterly basis to DVD), so the only real hassle is reinstalling the DAAP server and a few minor tweaks.
Still, it's damned unnerving, and has given me some food for thought. Going for a full-fledged RAID-enabled NAS box like many people seem to do these days is a bit on the pricey side (and doesn't let you swap disks around easily, which is why I stuck to external USB drives), but it seems I need to upgrade my storage somehow - for now, I'll be looking for a new USB external drive.
If I can't find any I'll just whip up something (storing a SHA1SUMS file in every photo folder seems an easy, low-nuisance and long-lasting way to do it), but if anyone knows (or has built) a simple solution for this, drop me a line (suggestions for storage solutions are also welcome).
Update: I got a Toshiba/PX1223E-1G32 320GB USB 2.0 for around Eur. 185, which isn't bad considering that the usual LaCie and Iomega junk costs around Eur. 160 for 250GB. Rather than buy a box containing (and masking) a number of cheaper disks with a proprietary controller (which is what the Iomega and LaCie devices above 250GB are), I'm going for the "cheap independent disks" approach. We'll see how it goes, since I have to reroute power cables to get it set up properly and can't be bothered at this time of night.