Actually the best protection is to remove incentive. Refer to
http://en.wikipedia.org/wiki/Gun_violence and look at gun violence in relation to the countries and notice the countries that are the least stable have the most gun violence. The countries with better care of people down on their luck have less, than say the U.S.
That being said I still think it is wise to own, and that it be known that people do own firearms. I do believe the government and criminals being the only armed people is a very bad situation. However I have to be realistic, if people have opportunity in their life that doesn't threaten their freedom, over 99% of them will take it. Rare excepts exist but we can't write the rule book on them since they never follow it to begin with.