I've never really used USB Flash Drives much. I had a very small one given to me so I could keep my resume and cover letters on it. Have no idea where it is now.
I'd love to have a 1T or 3T drive for backup storage. Preferably Apple's version with built-in wifi and streaming capabilities.
I do have a 160GB iPod classic that can be used as a USB Flash Drive for storage, but it's currently filled with music, TV shows, and movies. I don't really wanna erase / reformat it in case I ever need to restore lost media on iTunes.
And of course I have blank CDs and DVDs.