My first "carry gun" was decided for me. The armorer said "here's your weapons card, sign it."
After a few years of using either a .40 S&W Sig 229 or a S&W 649, I got turned onto the 1911 by a friend I blame for completely corrupting me. Back then I chose the Sig because I was persuaded by gun magazines it was the "$h!+", and I got both 40 S&W and 357 Sig barrels because I wanted the more powerful calibers. The 649, because I wanted a small snub revolver, and again, got the most powerful offering, the .357 magnum. Yet, I rarely used the 357 Sig or the .357 magnum in them.
Now, after I got corrupted, I chose the 1911 merely for its platform. And I got deeper and deeper into the pit. 5" .45 ACP at first; it was the natural choice. My plan was, after I cut my teeth on it, got used to it, and figured it out, I'd get something custom, built just right for me. And I did.
So, now I mostly carry a 9x23 LW Commander. I'll occasionally leave the 9mm barrel in it from time to time after a study day, and carry it that way out to dinner or wherever right after practice. Or, I'll carry a mirror image .45 ACP LW Commander when I'm lazy and haven't cleaned the 9x23 gun yet.
I got a Colt Cobra early this year, and carry that on rare occasions when I'm too ill from my disease for the weight of a Commander and spare mag. I had wanted an alloy Colt snub revolver for a couple years, and finally found one for the right price, in the right condition. Weight and comfort for me is everything after my diagnosis.
If its not a 1911, I don't have much of an interest nowadays. Luckily, one can get a 1911 in almost any caliber. So, the package drives my decision.