I'm lovvvvving Mac Funamizu's USB Memory Stick #6 concept, which would be made out of glass and provide a rather novel form of feedback. The idea is that lights of different colors--pink for images, blue for documents, green for movie files, for example--would accumulate as you added files, letting you "see" how much data, and what sort, you had on the thing.

My only gripe with the concept is the same gripe I have with other USB drive concepts, which is the same gripe I have with automobile ads: Most car commercials show their vehicle driving down a deserted country lane, not stuck in bumper-to-bumper traffic on the West Side Highway. Similarly, USB drive concepts are typically portrayed as being the only thing plugged into your computer, and on my octopus-like MacBook Pro I can't fit anything in an available USB slot unless it's the exact width of the slot itself.