Most likely a single pass with DBAN or a similar utility is all that's needed to make disks secure.
Disk destruction probably not necessary for standard business environments. http://sansforensics.wordpress.com/2009/01/15/overwriting-hard-drive-data/ "Opinions on the required or desired number of passes to correctly overwrite (wipe) a Hard Disk Drive are controversial, and have remained so even with organizations such as NIST stating that only a single drive wipe pass is needed to delete data such that it can not be recovered (that is a wipe of the data)." ~ Finally, powerful endpoint security that ISN'T a resource hog! ~ ~ <http://www.sunbeltsoftware.com/Business/VIPRE-Enterprise/> ~
