As much as I like the .45 for putting big holes in humans (never had to do that and hope I never do) there are other considerations. A big one is the fact that slow moving (relatively), large projectiles like the .45 ACP bullet won't penetrate things like a car door steel nearly as well as smaller, faster rounds. That's one area where the 9mm has it all over the .45. And in this modern world we live in being able to penetrate a car door might save your life some day.
Then there's the .40 S&W. It will also penetrate car doors but it's bigger than the 9mm. People tend to think of it as a compromise round but I don't buy that. It's a round with it's own set of features. And with modern ammo it has most of the good features of the 9mm and the .45 ACP. No it isn't as big as a .45 round but if you can't shoot through that car door to get bullets where someone is hiding and shooting at you then you have a big disadvantage. So I bought myself a .40 and I've been carrying it in my car. BTW most of my confrontations with idiots have come in cars in my life. People think they can do stuff to you and then get away and for a long time they could. If you don't believe that ride a bicycle around a while and see what happens. Some people love slow moving targets on bikes and will throw things at you that could easily kill you. Trust me I know. Now we are faced with a large number of fellow citizens that can also have a gun legally in their car. You just don't know which ones might go off on you although the percentages are very, very low. But it's that 1 in a million chance we have to worry about. So I want something that will penetrate car door steel and another problem area, car windshield glass. The ammo I use in my .40 will penetrate both (Hornady Critical Duty) which gives me a big boost in my protection IMO.
