Considering I haven't burned a single CD since I got one of these to store photos and laptop snapshots, I'm not sure a 20MB download is justified... But what the heck.
Despite keeping every scrap of code in CVS, every weekend I do a network mount of my laptops' filesystems and use ssync to backup /home or /Users (3 rotated snapshots, allowing me to go back three weeks if something goes seriously wrong - yes, I'm that careful).
However, ssync or rsync is a bad idea for backing up Mac OS X, due to the HFS resource forks that some legacy file formats still carry. I've yet to compile a HOWTO on scripted .dmg creation, but that's definetly an option to consider.
Unfortunately, time is not infinite.
Still on the backup/storage front: MacNN is reporting that LaCie (who hasn't updated their site yet) has launched an Ethernet disk (essentially an embedded XP file server). Now that's something interesting - I've got USB and Firewire cables everywhere, and don't see either technology as being scalable in either multi-access (i.e., simultaneous clients) bandwidth and "cable clutter", especially with 16- and 24-port Fast Ethernet switches on consumer shelves.
(It just makes too much sense.)
Provided it uses flash memory to hold the OS and has a built-in power supply (PSU bricks are a major pain), it might actually be interesting. Microsoft was prepping a cut-down XP kernel tuned for appliances, but since they were dumb enough to boot the Xbox from a HD, I'm not exactly holding my breath.