I have a bunch of flash drives lying around my office and they are all fat drives that block USB ports and need to be plugged into a port with a lot of room around it. This is a huge pain, especially if you are on a netbook or notebook with only a few ports.
LaCie has debuted a new flash drive called the MosKeyto that is tiny and looks more like one of those nano receivers for wireless mice and keyboards than a flash drive. The little drive measures 21 x 16 x 10mm and weighs 10g. You can plug the tiny drive into the USB port and just leave it if you want.