Bridging off the "on the go charging article"

I am looking for a method of keeping important data safe.
This ranges from useful data- manuals, books, teaching stuff,
to Emotional/Valuable stuff- family pictures, etc.

At this point in time I have a NAS-a network storage box, on site, and use several cloud based backups- Google + Sugarsync, but I would be more comfortable with a more portable solution.

I saw what appears to be an interesting solution MDISC, like a hardened DVD/Blueray, but not sure if worth the time/trouble.

Looking for comments, suggestions.