Here's a nifty little product if you're a Windows user - Rebit is a pocket-sized back-up that is so easy to use that even my Mom could master it (and she still calls her computer "that TV thing"). You can even go back to older versions of saved documents, as it catalogues past copies of your files.
Simply plug in the Rebit to your USB port, click "OK" and all your files are downloaded onto the machine. No configuration and no extra cables, since it powers itself via USB. 60G is $169, 80G $189 and 120G $219.