I use this portable hard drive:
http://accessories.us.dell.com/sna/p...15&lid=1003767
I used to use large thumb drives but dropped one and it smashed into a million pieces. I lost a few articles and writings that I could never recover. Since then, i've backed up everything I could ever need on this device. It's encrypted for security, and is really durable. It should do what you are looking to do.