As recent events in history have taught us there comes a time when your safety may depend on your ability to repel violent attackers. We staff our police departments for peace time, selecting a level that can respond to most of the crimes at any given time within a reasonable amount of time. During a wide scale disaster, emergency or situation that inspires social unrest like we've witnessed recently in the Arab Spring, we can't rely on the police to protect us. There will be too many victims, too many perpetrators for a police department staffed for peace time to assist everyone. Even during a typical day police response times vary greatly.
I live in a working class suburb in St Louis county. We have a great police department, and for 2010 their average response time to a 911 call was around 2 minutes. The time I summoned police they had two cars on my street in 60 seconds. That's pretty impressive.
However, if you travel 5 miles east you end up in a rougher part of town, the north side of St Louis city. Average police response times in the Lou for 2010 were around 30 minutes. That's a significant disparity. If a person who lives within the city expects the police to arrive in time to stop a crime they are likely to be disappointed. If there was a tornado, earthquake or terrorist attack then those average response times would climb dramatically.
This inspires a lot of people to own a firearm and learn how to use it. It can be considered as an insurance policy- you hope you never need to use it but you are very appreciative when it is there. It can be life changing if it's needed and you don't have it.
So what sort of gun is best? The one you have and know how to use. Any firearm is better than no firearm. Unlike most people I know who are firearms enthusiasts, I am not a gun snob. Granpa's old shotgun is a reasonable gun to use to protect your family. It may not be ideal, but in truth all hand-held firearms are a compromise. If we knew we had to protect our family on a given day we'd all likely choose a more powerful tool, like a tank. Backed up by a team with flame-throwers. Backed up by a team of snipers. But since that isn't feasible we should make the most of the tools at hand.
Firearms are like many things, it's the training and the practice, not the tool, that matters. A great musician can play a cheap instrument well. Conversely I could only manage terrible noises if I was handed a violin today, even if it was a Stradivarius. I'm sure a professional race driver could operate my car around a track faster than I, and I'm pretty sure I'd be rubbish in a Formula 1 car.
So if you are thinking about getting a firearm to protect yourself and your family, don't stress over picking the "right" thing. Every person is going to have their own opinions, and most of them are steeped in their own bias and not on statistics. If you'd like to read a report based on real world defensive firearm effectiveness, I recommend An Alternate Look at Handgun Stopping Power by Greg Ellifritz. It's a rational look at the topic.
But more importantly, get training. Whether you agree with their politics or not, the NRA has a robust training program and a nationwide trainer infrastructure. You can find a class in your area with their Course Search Tool. I recommend Personal Protection in the Home as a starter course.
Of course if you are in or around St Louis, drop me a line and I'll send you an invite to my next class or set up some training time.