Rugged USB flash stick

[James Crippen]

This thing looks like it could stand up to some serious fieldwork
abuse and still work just fine. It might serve as a good backup
device, even better than recording to CD-Rs. And with sizes up to 32
GB you could keep an awful lot of audio recordings on it. It also
seems to have a very fast read-write speed, so you can use it with
larger files more easily.

http://www.corsair.com/products/survivor/default.aspx

Their website doesn't list (for me) any places to buy it, but Google
gives plenty of results. Also here's a good review of the device,
which includes links to retailers:

http://www.everythingusb.com/corsair_flash_survivor_gt_8gb_12805.html

Perhaps you could tuck one or two emergency matches into the case as well...

Cheers,
James