It's a good idea to have a second hard-disk drive in your computer, or even a third. It's also a good idea to buy, and use, those pocket-sized USB 2.0 or FireWire hard-drives ... the kind from companies like DataStor that neatly fit into your pocket, or into a safe-deposit box.
If you can reliably say that you've got a fresh copy of the information, and that one of those copies is in a fireproof room about five miles away from here, next to that really neat cappucino shop, then ...