The guys at THG take a look at ten new, higher capacity hard drives & attempt to shed some light on the question of whether you should upgrade your storage capacity. IMO, more's always better, as long as you don't out-grow your backup strategy...

"Data density has increased steadily from generation to generation, which is the main reason why a 160 GB drive needed two or three platters only a few years ago, while the same capacity point can be realized with only a single platter today."