A look into my modest collection of self-defense tools kind of settles the issue as far as what I personally prefer for a self-defense pistol cartridge.
Middle row (l to r): Springfield Armory 1911A1, Colt 1911, Smith and Wesson M1917
Bottom (l to r): Sig P220, Glock Model 21, Smith and Wesson M&P 45
I've got a few other handguns in other calibers in the safes too, but heavy and slow works for me, it seems. Not knocking other choices, but I'll stick with the .45.