Jeffs; There are plenty of formatting programs that "zero" all data locations on a HD, they typically do not format a drive quickly, a 20GB drive may take an hour. Some write over a spot twice, and even totally re-write the master and sub directory blocks. Most formatting programs, especially Quick formats usually just mark the directory block (AKA FAT) as empty, essentially saying the drive is empty, but has not erased anything until new data is written over older data.....
To really really make your drive un readable change file formats, and zero all the data..... For example FAT32 to NTFS.
Or just do like they do on the tv news..... Smash it with a hammer.....
Yah, my first computer was $3K too.... Mac LCII With 100Meg HD Still have it...
Free Data Destruction Software:
http://pcsupport.about.com/od/toolso...n-software.htm