I carry a S&W model 13 with a four inch barrel. I carry one extra speed-loader. That's what I carry because that is what I shoot best.

I focus more on avoiding situations that will expose me to attack than I do worrying over whether 12 rounds of .357 Magnum are enough. I don't go inside banks or use walk up ATM's. I don't shop in convenience stores in the middle of the night, etc.

Choosing and carrying a particular firearm is only part of a personal security plan. JMHO