I recently bought a portable media player(mp3 player that can also show pictures and videos) that holds 60 gigs, so I've been thinking about putting survival refence info on it as well. Battery life does limit its usefullness(rated at 15 hours audio, 5 hours video), but since it isn't used for communication, there's no need to save it(unless I wanted to use the mic to record my last will and testament...chances are no one would think to look for that anyway). Also, if I was stranded with my vehicle, the car battery could extend the battery life greatly, and indefinitely if I didn't use up the gas for heating.

I would mostly use the info for entertainment and training, but it could be useful in a survival situation as well. I was thinking simple diagrams of shelters, traps/snares, knots, types of fires, primitive tools, maybe edible plants, etc, would be very helpful, with minimal battery drain. You can read tons of survival info, but for those of us that don't practice survival skills as much as we'd like, its easy for those things to slip our minds.