This is an interesting thread to read, because me and my girlfriend discuss this frequently.
Well...frequently...we've discussed it. More than once.
Personally, I'm of the opinion that it shouldn't just be criminals and the state tat are allowed to arm themselves, as that leaves citizens at a distinct disadvantage. There are fair arguments against people being allowed to carry firearms, especially here in the UK, that I have a hard time arguing against, including the fact that there are so many half wits out there that it would indeed be dangerous.
However, during the course of the discussions with my better half she felt particularly aggrieved (remember, she's German), when I pointed out that Hitler believed the citizenry should be disarmed, as did Pol Pot, Stalin etc etc, yet the peace loving hippy Ghandi firmly believed that one of the most destructive things the British ever did to the people of India was to disarm them and believed that it should be the right of all people to carry weapons to defend themselves.
As @DumbRedneck (I think) pointed out - criminals don't care about laws that restrict access to weapons, so it's arguably irresponsible, in your duty towards your families and loved ones, not to be armed.
It's such a long complicated topic and I love discussing it, especially since my mind isn't made up firmly one way or the other, albeit leaning slightly towards pro gun