I almost always use truecrypt to erase my disks completely when I'm re-purposing them or before throwing them away or giving them to someone else. You never kn

I almost always use truecrypt to erase my disks completely when I'm re-purposing them or before throwing them away or giving them to someone else. You never know where they are going to end-up years later. I just bang randomly on my keyboard when Truecrypt asks for a password and then let it overwrite the drive. It's pretty fast too and works the same way on all platforms.