He misses two key points.
First, secure erasing of hard drive contents is built into Mac OS X. Launch Disk Utility, click on the volume or drive you want to erase, then click on “security options…”. I just zero out all data, but you can be up to 35 times more paranoid than I am.
If you want to ditch a partitioned drive, I would suggest repartitioning the drive down to a single partition. This allows for a single erase-and-zero pass. Takes just as long but you don’t have to mess with it in the middle.
Secondly, don’t forget to erase the data on broken hard drives! Just because a drive no longer works does not mean the data is inaccessible! Often, carefully swapping the controller board on a drive is enough to restore it to working order long enough to pull off the data. Professional recovery services (and really careful hackers) can even swap the platters from a dead drive to a working drive to recover data!
Me? I take dead drives apart. They have amazingly powerful magnets inside, along with all kinds of very useful screws, washers, nuts, coils, and other fiddly bits.
The platters, obviously, contain the data and they should be destroyed. I run one of the magnets over them upon removal and then keep a stack of the platters around as they have proven to be incredibly useful! The platters have been used for everything as clamp pads for gluing stuff to spacers to level a table or work surface to being used by my son as part of a bug house.
Note that not all platters are made of metal! Some are made of glass! So, if you plan on smacking the platters with a hammer, be careful!!
Or, do what I did when I discovered this: Set up a high speed photog kit and drop a pinball on it!