Nowadays, arthritis and all, I am no longer within the parameters of your survey.
But way back when (that is, about two years ago)? Oh, the .45 ACP, but in my case the AMT .45 Backup in a front pants pocket.
I normally carry a 9mm about 95% of the time loaded with HST or Ranger T. The only time I go for the 45 is when I am in the Mtns and then I load it with Extreme Penetrators for Lehigh for the black bears and a mag of 230fmj for backup. I know I need to get a 10mm or 41mag or larger soon.