a normal magnet or even a super strong hdd magnet wont do anything to the hdd to destroy it. you need a special machine that you put the hdd in and it will pulse like a 300guass strength magnetic beam and destroy it.
taking a butane torch and applying it to all platters will do (make sure to shove the flame in between them)
another great way is to drill a hole thru the hdd, and you will go thru all the platters.
and hdd is like the layers or the eaths crust. each one goes back in time. that's why the hdd can be recovered up to 50 times deep, or 50 rewrites. (but that's with an electron microscope)
overwriting your files about 2 or 3 times are plenty sufficient even for the experts. this is the best shredder to get:
http://www.analogx.com/contents/download/system/shred.htm
and there really is no point in shreding, or even doing those fun destructive activities, unless you know somebody could recover some info and get you in trouble, or steal your credit numbers.
Mr X
Better shredder...
dd if=/dev/urandom of=/dev/hda bs=1M
Run that 3, 4, 5, ..., 50000 times for all I care.
