i use 2 data base files on 2 different usbs.. one database holds the key for the other that contains my passphrase. so someone would actually have to have both usb's and hack the password for the first one(its weaker so i can remember it) in order to gain access to the other, unhackable database.
What if you lose one of them?
I hope you have backups of both...
I have back ups on 2 laptops and 2 usb keys.. They won't be getting lost :)