Darik's Boot And Nuke

A question came up in the forums about the best way to erase a hard disk. All respondents unanimously pointed to Darik's Boot and Nuke. According to the site:

Darik's Boot and Nuke ("DBAN") is a self-contained boot disk that securely wipes the hard disks of most computers. DBAN will automatically and completely delete the contents of any hard disk that it can detect, which makes it an appropriate utility for bulk or emergency data destruction.

Now it can't get any simpler than that.

Why would you want to do such a thing? Well, let's say you're selling your computer. You'll want to make sure there's no trace whatsoever of any incriminating data. It's happened many times before that a compnay would sell a bunch of their old systems and some newshounds still managed to recover some old files, much to the seller's embarrassment.