Had to write a blog post on this …
Drobo allows you hotswap SATA hard drives in and out of it.
Just pop it open (yes … while its plugged in) and switch out hard drives as you wish.
It has 4 bays and can hold up to 16TB of Data. It magically writes and rewrites your data across all the drives it is using at the time … scary good eh?
Runs USB 2.0 or Firewire 800 (oooooh) … definitely up my ‘most coveted items’ list, right next to the Macbook Air (still searching for a sugar mommy to help out with that one).