Putting sensitive documents in a thumbdrive isn't a very good idea. And if you don't want them falling in the wrong hands, you can get this voice authenticating USB drive to ensure no one snooping on your sensitive stuff.

The thumbdrive looks like any other regular one, but it uses voice recognition technology and will only grant access to a password spoken by the owner. There's no installation required, but once you plug it in just speak the password, and it will authenticate you to start keeping your files in it.

[Hammacher Schlemmer via Cool Material]