@Setanta,
First anything can be used in a harmful way and even a deadly way up to the police in my home town once beating to death a gentleman with heavy meg lights!
Now before the Taser if someone is coming at you with a knife or even a heavy club the police had little choice but to used lethal force and that is not the case now thank to the taser.
And yes the taser can also be used in place of the billy club but then unless you had a week heart getting taser is far far safer then having bones broken including the bones in your skull!
All in all we are all safer with tasers existing then not in my opinion.
Oh I had work around high voltage equipments for 33 years and a a result had been shock more then once with similar voltages to a taser and seen co-workers also shock with no lasting harm. It is however not fun but then having bones broken by a billy clubs would be less fun.