.45 is my personal preference.
Well in the spirit of this silly thread:
Frankly anyone who carries anything less than a 454 Casull likely has to pee sitting down. Furthermore that is the bottom end, you really need a .500 S&W to be sure you are not under-gunned.
My carry gun is a 7.5 inch .45/70 magnum research revolver. Ported you ask?, nah, that is for girls. I keep in training by taking it out every few weeks and firing 3 rounds. I like the original load, a 500 grain lead bullet with 70 grains of black powder. That way if I miss I can tactically evade in the cloud of smoke.
My back-up is a S&W revolver in.500 S&W with a 2 inch barrel, ported. I never fire more than one round at a training session. Frankly the fireball from the round is likely to ignite any intruder at less than 4 yards, or at least blind him for some seconds while I make my tactical evasion. I shut my eyes as I shoot it to avoid being blinded by the fireball, one of the tricks real operators know, which the general public, Rangers , Police and Seals would not.
I use a shoulder holster for the Magnum research, pretty comfortable except at the beach. My orthopedic doctor has pointed out I now have a very slight curvature of the spine but well, it might also be related to the cartilage problems I have from shooting the pistol one-handed. I use a special “crotch” holster to conceal the 2 inch 500 S&W. Has the added advantage that the ladies seem to notice, if you know what I mean.
Reason for a few weeks between 4 round range sessions (3 45/70, 1 500 S&W) is to allow my ligaments and tendons to heal. But hey, that is the price you pay for not shooting a pansy round like the 44 magnum or 454 Casull. Have some self respect dude, if you shoot them you might as well get a “Lady Smith”. Pink might match your color scheme.
So this entire debate of 9mm vs 45 is kind of like 8 year olds debating wither the .22 cal pump daisy rifle is as good as the 5 mm Sheridan air rifle. Grow up ladies.