I am a pack rat sans compare. Just about every digital piece of flotsam that I have ever created on any computer is dutifully transferred from one computer to the next. I keep everything aggregated in one or two places, so it's not hard to transfer without keeping track of the bits.

If you really care that much about my backup strategies: the core of my data is backed up via Dropbox. Things which are either too big or not important enough to be in Dropbox (I have 50G storage there) are backed up automatically and wirelessly from laptop(s) to network drive. The network drive is backed up to an external drive.

And I still feel like I'm not quite backed up enough (what if a power surge fried both the network drive and the external drive? never mind the UPS/surge unit I have on them)... I have issues with my possessions.