I currently have four USB drives in a tiny pouch in my bag. One drive is for work, one is for personal files, one is a backup of the projects during my final year in school, while the last drive is just for random stuff. Needless to say, teeny tiny pouches don’t really make for good USB storage cases because I’ve lost a couple of drives while in transit.
A novel and pretty presentable way of keeping a closer eye on your drives is with Memory City from Koziol. It’s a molded plastic case with slots where you can stick your USB drives and memory cards in. Once you’ve got enough drives on the thing, it will start to look more and more like a (you guessed it) memory city.
There’s enough slots for 3 micro SD cards, 3 SD cards, 4 USB sticks (just right for me) but just 3 USB lids (although you can just fasten the lid on to the bottom part of your USB drive.) Memory City goes for 9,95 € (~$14 USD), which is already inclusive of VAT and shipping. You can get one from Design 3000 or Made in Design if you want one.