CagnidaDesign posted a pretty sweet concept on their site called Tempo – this is an external hard drive in the shape of a trash can that stores everything you delete.

Intended to protect the user from accidentally deleting files, it can also be used as an external storage device. As you delete files, they are automatically copied to the TEMPO. As it fills up, led’s light the “can” from the bottom up, informing you of how much space is available.