The absolute best thing is an industrial shredder. But as those are pricey, you can use a destruction service that will send you a report saying the drive was destroyed. The report satisfies auditors if you're in a business environment. Still on the physical destruction path, you can open up the drive and use sandpaper or similar to destroy the coating on each of the platters. Or take it to the firing range & open up with your favorite shotgun.
What most do, though, is use software to erase the drive's contents. Search for something that does a DoD Wipe (DoD=Dept. of Defense). This process does multiple passes over the drive with each pass writing different bit patterns. The result is a drive whose contents cannot be read or determined by analysis of the residual magnetic fields.
If you have a need to wipe a number of drives, there are
appliances that will do the wipe for you and again, produce auditor-friendly reports.
The advantage to the DoD and appliance wipes is that the drives can be re-used.