I have my NSA INFOSEC cert and the paranoia of some posters is a little unrealistic. The multipass drive wipe is accepted for personal, corporate and most government use. If you're dumping the computer (not donating for reuse) just take the drive out and damage it. If you're really concerned drill a hole through the platters. If people's lives or national security is at stake . . . well, the conversation wouldn't need to be happening here.

You don't want to be the easy target. Any of the above takes care of that.

Side note - taking the drive apart results in the best wall stud finder made. The magnet can be removed and is strong enough to hold itself to the drywall screws. :-)