Re: @Chris Lively
Cars and walking have a purpose other than killing. To compare walking to gun ownership because "some people get hurt walking" misses the issue entirely. If anything, the comparison demonstrates how tenuous the similarities between guns and cars/walking really are. (not to mention that in the example you gave, walking is a passive action - it's akin to banning people from going into office buildings because of 9/11).
Even if, as some people claim, a car is a "weapon", as it can be used to murder, it requires premeditation to get in the car, start it up, put it in gear, release handbrake, drive out of driveway, into street, then navigate to wherever I want to kill someone. It's not a case of pulling a trigger, and the intended purpose of a car is not to kill - so even if I *wanted* to, I still quite possibly couldn't kill anyone with it. What's more, despite the number of cars in the world (billions) the number of intentional killings using them is miniscule.
Lastly, a car doesn't always kill. I've had car accidents where both cars were written off, and no-one was injured. In fact the number of accidents involving no injuries is much higher than the accidents that do result in injuries - I've not heard of someone taking a bullet in the head and not sustaining any injuries, but will happily stand corrected.
Using a gun for suicide requires no thought - pick up gun, pull trigger. Like it or not, people make decisions that they regret later, and suicides that require more time/thought result in less chance of people going through with it. It's why they have councillors at popular bridge jumping spots - not to "fix" the issues people have, but to at least give them time to think. If you make someone go to a lot of effort to kill themselves, they're at least going to have to give the issue more thought - a gun removes that second chance.
"how much should society give up to make it safer for one person?"
^Exactly. You've hit the nail on the head with this question. Why should we be happy with people blowing their own brains out, either intentionally or unintentionally, simply so that a few paranoid types can "feel a sense of security"? If safety is measured as the likelihood of being killed or injured by a weapon, then guns need to be controlled. Why should society be happy for shootings to be commonplace when it's only being done to placate the few who are so insecure so as to need a placebo for their issues? With effective gun control, society gives up nothing. With the way things are, many people are at risk of injury so that one person can have the illusion of safety.
The "uses" of a gun are limited to killing - that's their sole purpose. They can be used to intimidate, but only because they're designed to kill. They give a sense of security, but only because they're designed to kill. Recreation is the only other use, and using a gun for recreation doesn't require it to be loaded/kept at home.