Having a terabyte or two of game backups, movies, music, and books might be very useful for long car trips or the rv crowd. I've got the Patriot Gauntlet, but I might prefer the newer Seagate. Look for forums to see the quirks and amount of support for these devices.
Question: does a Titanium backup of a game reinstall with the data so that game progress can be resumed?
A solar charger, edible plant database, wild game preparation and recipes, survivalist manuals might appeal to the paranoid among us. Or boy scouts.