I work for a company, where one of there areas of work includes dealing with other companies hard drives, often with sensitive data on, we first preform a low level format on them, then we have to hit them with a hammer for about 5 - 10mins till the disk surface itself is completly damaged all over. They seem to be happy with handing over there computer/HD's, if we agree to preform the above procedure on them, but i imagine there will be someone with some way out there to recover info on that disks, even when physically damaged. :/