Remember that USB flash drives are not a silver bullet. Yes, USB flash drives are solid-state (no moving parts), but they can be taken out by power surges, magnetic fields (if strong enough), and other things.
The only real way to protect what you have is to make periodic backups of the files and store them somewhere else.(ie, not on the computer you are backing up) also it is a really good idea to periodically check said backups to verify that they are good and can be recovered. Flash drives are good for this. I use two 1G drives and make a backup on a weekly basis. (The spare goes into the fireproof safe) This is one area that people without a lot of technical experience tend to overlook, but in the IT industry, we deal with on a daily basis.
just my 2c
-paul
