If you have a to comply with HIPAA, Sarbanes-Oxley, protect trade secrets, or store Personally Identifiable Information you already know that a discarded hard drive can come back to bite you. So, a while ago I wrote an article explaining how to erase a hard drive completely.
Here is my absolute favorite way to be sure that data gets real gone: The guys at Data Devastation will sanitize your hard drive with a .357 magnum. Or an AK-47 for that matter.
For about $60, these pros will take your drive to a range, unleash a fusillade that will wipe it to Department of Defense specs, and provide physical evidence that the data is gone.
You can even choose the caliber.