Before I throw my two cents worth into this unending and unwinnable argument, I will wish you all a Merry Christmas.
My take on which gun, how many rounds, extra mags or speed loaders, etc. is that almost all of it is meaningless if you can't shoot.
Shot placement is more important than caliber in most cases (not a big fan of .22 or .25, even .32 or .380). That said, a .22 in a vital organ is much better than a .44 in a wall, the woods, or somewhere else besides the target.
Carry a gun that is concealable with a comfortable rig. Shoot it regularly and be proficient.
A guy that I occasionally shoot with carries a Smith lightweight .44, think it is a 329PD (I think, anyway). Nice gun; I shot it once, opened the cylinder, and handed it back. One and done here. He doesn't practice much because it hurts. Can't hit a 12" steel plate at 10 yards because he flinches so much. Useless.
Personally, over the many years I've had my CCW, I've carried everything from a 4" N-frame (M28), full-size and commander size 1911s, BHP, M&P40, various Glocks. I'm about 160lbs, so weather dictates what I carry as much as anything. Yesterday, under my coat, I carried my favorite 1911. Can't do that in July with a t-shirt, but a G43 with an IWB rig works fine then. I practice and am fairly proficient with all of them.
Before I had my own backyard range, I used to spend a whole lot of time at the indoor range in Asheville. Quite a show watching folks spray rounds with high-cap mags and hit very little. We have a saying in both USPSA and SASS: "You can't miss fast enough to win". Goes for self-defense as well. Too many folks spend too much time worrying about how many rounds they carry rather than worry about where they go when the trigger is pulled.
Nothing wrong with carrying a six-gun. Takes practice though - got to be willing to get proficient double action (not cock, aim, and pull - unless you carry some version of the SAA). As someone pointed out above, odds are that you won't need 30+ rounds in a gunfight. Turn off the TV.....
A reliable weapon with an accomplished, prepared shooter will win out. Caliber is secondary. I know, stopping power is important, but a lot of pros (cops & military) carry 9's rather than .40's or .45's, and they do lots of research into what's best in most situations.
Guess you could carry a full-out .38 super race gun with 5 spare mags under a trenchcoat in July to be completely prepared, right? Or you could be sure that every one of your 5, 6, 7, or 8 rounds hits the target all of the time from your easily concealed weapon that you can comfortably carry anywhere without notice.
Might add a bit of situational awareness to the equation as well. If you think an area might be unsafe, and you can avoid being there (regardless of whether you have a right to be there), avoid being there.
At least that's my, probably worthless, two cents worth.
