The iMac is one beautiful, powerful machine. It doesn’t take a lot of space on its own but if you are running short on space, you can always get the Twelve South BackPack to store your hard drives and other things. This is a storage shelf that installs on the back of your iMac and takes your peripherals off your desk.
The Backpack shelf can hold up to 35 pounds of hard drives. It is compatible with iMacs 21 to 27 inches. You can get it in Matte Black and Silver versions.[where to find it]