Outstanding thread! However, have you considered...
Special thanks to First Sgt and follow-up by Bark'n. Well Done!
However, to carry a bit further on, why assume that the perp isn't wearing body armor? More and more BGs are using it, in the commission of a crime. If you have the money, and the contacts, it's available.
I'd go with the first posters mentioned here, and when in position to challenge and engage, assume two handed stance, if possible, then if perp doesn't yield, go for the head. Period.
I carry Glocks- a 21 and 30, at all times when out, one or the other, at home. Both are .45acp, and loaded with Winchester PDX1 ammo. (Home invasions are on the rise here.) I've used .45acp for forty years, and though I've used/carried both lighter and heavier calibers, the .45acp is my personal favorite.
All that being said, Clint Smith said, "Your pistol is what you use, to get back to the rifle or shotgun you shouldn't have put down in the first place..." NO pistol is as effective as a "guaranteed" one stop shot to COM... A bullet transferring the skull, and its contents, to destroy the brain stem, IS a one shot stop. NOT a guaranteed shot, with a pistol, but better than COM, if you only have seconds, are in the ideal position, and have the drop on the perp.
IF you have to pop the cap, shoot until the threat is totally neutralized.
NEVER shoot to wound. As I postulated, he may be wearing body armor. At best you'll irritate him. Worst? You're dead, and so are innocents.
Again, go back and read First Sgt's and Bark'n's posts, and add in the possibility of body armor, and then think of how you'd act. I don't think their posts can be improved.