The folks here are quite right in that you need to learn how to use a pistol or revolver before you ever decide to carry. I personally will have a Glock 27 most of the time loaded with hydra shocks. But then again sometimes I'll carry a Glock 23 (just like the ones a lot of cops use). Both are 40 caliber, and do anything I ask for. Still at times I carry a Sig P220, but I really don't have a lot of confidence in that gun (not a 1911A1), not the round itself. I have not carryied a revolver in several years now, but when I did it was a Colt Diamondback loaded with hydra shocks. I liked it better that the Ruger .357 I carried as well, but the Ruger was more gun. I learned to dislike the 9mm back when I was in the Army.Shot placement is the most important thing. Like some of the others have said, doesn't matter how big it is if you can't hit with it. I like a 45, used to have a 10mm, now I keep a 380. Not that I can't handle the bigger pistols, its just the 380 is nice and light, plus I hit what I aim at.
Now for the second part of this equation. Have you considered what can happen if you carry? What if you have to use it? Are you prepared to deal with the results? If you shoot, you are shooting to stop a threat, which is quite likely to end up in you taking someone's life.
So here's what you gotta be able to do if you want to carry a weapon. Fist be able to use it without shooting yourself or worse yet. Be able to hit what you aim at over and over. And lastly just because you have somekind of an outstanding piece, it's worthless if you can't maintain it. Forget all the hand load crap, and just stick with a well made factory round. That's why I use hydrashocks most of the time. In my 45's I use nothing but 230 grain hardball because it works everytime. So find a round your comfortable with, and then learn to shoot it