I read about half of the first page, then skipped through the rest.
First, to answer your question: it depends on your body type. Can you conceal the fat double stack of a G19? If so, look into it. It's my carry weapon of choice. About 6000 rounds through it and not one failure of any kind. Glock makes single stack weapons, but if I was going to go single, I'd go to my backup weapon - 1911. Nice single stack, easy to conceal, tons of varieties and options. 1911's can go from a few hundred dollars to a small house - do your homework
Second - stopping power is a myth. Typically, shooting someone with a .45ACP is not going to make an immediate difference over shooting someone with a 9mm. There are external circumstances, like clothing, that can interfere, but in general shot placement is key - not caliber. Plus, a typical 9mm is going to have around double the capacity.
Third, I saw some talk about home defense weapons. A 18" pump shotgun filled with 00 buck is most likely going to be the best remedy. It's what I keep. Round in the chamber, safety on. The sound of racking a shotgun is not going to scare off a seasoned criminal who's in your house. Shotguns don't hit everything in the room, though, you still have to be a decent shot. At 10', 00 buck may make a 3-4" shot circle (don't quote me on those figures).
Finally, and most importantly - do not lock up HD gun when you're home. Do not hide them from your kids. Show them to your kids, explain the dangers, take them shooting with you, get them involved in competitions, get them professional training. Hiding things from kids does NOT protect them from them, it usually only makes them more curious. I think we all remember our childhood. I know what happened when my parents told me I wasn't allowed to drink or smoke
My range rents weapons, so if yours doesn't, call around and see if other local ranges do.