Mason line (nylon) is also impressive.

As far as keychain drives, I'd suggest the Lexar "Jump Drive" secure. This drive comes with encyption software that also partitions the drive into a "public" and "private" area. Another really cool drive is the Sandisk waterproof drive. Sandisk Waterproof Drive

Now, for a word on file formats.

The MS Word .doc format is NOT universal - but RTF and TXT are. PDF (Adobe Acrobat) documents are nearly universal.

As far as images - jpg and gif are universal, much smaller than tiff (or tif) and work fine..

BUT....

A scan of your documents is NOT NOT NOT a legal copy of your documents at all and is quite worthless in a situation where there is a need for an original document.

Unfortunately, this means that even if you have a marvelous stash of data on your key drive and your house burns, except as a reference to help you deal with the courts and all that, these scans are of little use. I speak from the experience of my home burning to the ground and having lost all the documents therein, which is why I have THREE fire safes now.

As far as medical data - human-readable data is what we need on the scene. I can assure you that we WON'T recognize or have the ability to read a USB drive if we need to pry you out of a car - but is we see a medic-alert tag, we can and will look at that.