Even if having a gun won't make you a killer, if you have easy access to guns (as in the USA everybody seems to have) this will make easier for mad people to kill. Just sayin'.
In Europe and Japan, just to name some examples, there has been gun control for ages and that has been more good than bad. People in my country overthrew a dictatorship only 30 years ago, although people had no guns. Only a handful of people were killed in the process. Although times have changed, I still believe we don't need guns to defend our rights and our freedoms. Violence only generates more violence.