i use suredelete. it can wipe your drive multiple times and its free. and you can do specific directories and such http://www.pcworld.com/downloads/file/fid,22393-order,4-page,1-c,harddisk/description.html
Easy use Thermite. http://www.youtube.com/watch?v=O945Rznz8N4 another video http://www.youtube.com/watch?v=Ij6huKsW0Z0
I have been able to recover data after multiple formats, so reformatting isnt an option. Among other options, here is one more http://www.killdisk.com/
Evidence Eraser. From their website: "Evidence Eraser meets the standards set by the U.S. Department of Defense for disk sanitization. If our technology is good enough to get rid of sensitive information for the Department of Defense, you can be sure itâll get rid of everything you need it" http://www.evidenceeraser.com
like this- http://www.youtube.com/watch?v=I5W9b-U_kQY&feature=related but using electric drill instead(assuming you have one in garage) btw-there is plenty of videos about this on youtube. just type "destroy hard drive"
I actually tried this with an ordinary electric drill and its not easy/fast. There is a large amount of metal in the hard drive case, presumably to act as a heat sink so its pretty tough on the drill bit to drill through. I found it much easier to remove the screws on the drive, open the case and then go to town on the platters directly.