There are all sorts of bits and pieces I'd be annoyed to lose, but the only thing I'd really miss are my novels. And the thing about my novels is that they're works in progress. Any form of back-up that implies a settled, permanent form - burning them onto CD, for instance - sends entirely the wrong message.
If my printer wasn't so temperamental, I'd save them as hard copies. I'd be able to read them on the bus and scribble corrections with a pen - two big advantages for the low-tech back-up. But I'm sure they would be classed as "clutter", and I can't deny that they take up space.
The only other back-up I've got on with is posting chapters to creativeiron. It's off-site, which is a great advantage, and I can solicit feedback at the same time. On the other hand, when I get no feedback - or even ego-stroking but insubstantial feedback like "I really enjoyed this" - I lose heart and wonder why I'm bothering.
As I said, this is only partly the problem. I'm sure I could, if I really put my mind to it, find a suitable method and get myself into the backing-up habit. But TVTropes, to take a not-quite-random example, has a stronger claim on my attention. And until I do have a data disaster, it's hard to see that changing.