The original BackPack was a handy little shelf that you could attach to your iMac or Apple Display to get an external hard drive off your desk. A new version of the shelf has been released with pegs and cable management rails.
We've talked before about using your monitor as a storage system, along with the original BackPack. The newest iteration attaches to an iMac or Apple Display, supports up to 1.6kg, and comes with pegs so you can stack more items on it. If you'd rather not have it hidden away, the BackPack 2 can also clip to the front of your Mac for easy access.
The BackPack 2 costs $US34.99 plus $US30 shipping to Australia.
BackPack 2 [Twelve South]