Y'know, if one lives out in the boonies (like I did growing up), I can see owning a shotgun and a rifle. Not only are there critters that can be dangerous, but the police are sometimes a long way away.
But living in the suburbs or in urban areas, I see no reason at all to own a firearm. There's almost always people around, and the police are almost never that far away. Besides, if someone really wants to kill you, they're usually going to get the drop on you - you'll never have time to draw a weapon. What's more, having a firearm in the house presents a dangerous temptation to anyone who knows it's there, whether it's a ticked-off (or depressed) grown man or a too-curious kid who wants to show it off to his friends. And if it's locked up, it will take too long to get to it if one has only seconds to respond.
Gun-lovers used to say they think everyone should have firearms like in Switzerland. Anymore, I agree...because Switzerland's firearms are much stricter than anywhere in America. People in Switzerland live longer, too.