[insert round type here] which strikes the perfect balance for my lifestyle and threat probability.
That pretty much sums it up.
IMO, defense is a personal choice of what compromises an individual is willing to make. Each approach has strengths and weaknesses, and each approach is not appropriate for each individual.
Firearms stop threats in one of two ways:
1. The mental stop.
The mental stop occurs because the threat either sees the gun, and does NOT want to be shot, OR, because the threat has been shot, and does not want to be shot again, despite being physically capable of continuing their assault.
2. The physical stop.
The physical stop occurs because the threat has sustained enough physical damage to prevent further physical action.
Every firearm has the potential to achieve a mental stop. While handguns are weak compared to rifles, even a .22 short could produce the pain and damage that most people would gladly avoid if they could.
Every firearm has the potential to achieve a physical stop. While the human body is pretty tough, even an air-gun has the potential to achieve a physical stop if it hits the right spot as shown below:
NYC man killed by air-rifle :
http://www.nytimes.com/2000/07/22/n...h-in-brooklyn-highlights-air-gun-dangers.html
However, the more powerful the round, the greater the potential to achieve a physical stop.
My choice is .45ACP, and I wouldn't carry anything less powerful than a 9mm if given a choice. While the more powerful guns are larger, heavier, and more challenging to conceal, that is a compromise I am willing to make to have the greater potential of achieving a physical stop, if needed.
IMO, as long as an individual knows and accepts the strengths and weaknesses of their firearm, it doesn't matter what they carry, as it is a personal choice.