And this is where I jump in with more "know what you know" reality. I am not going to say anyone is wrong about their defensive gun choices, but I will make sure you understand your actual rational for making that choice.In all honesty my home defense gun is the same gun I carry everyday. More importantly know the layout of your home. Where your kids sleep. Angles. Over penetration through walls and who may be effected or on the other side. Practice moving through your house/apartment. My house is 1600 square feet. Single level. I don't have a staircase for a height advantage but I can move quickly through my house and close distance before entry is made. Harden your residence. Door jams, windows, garage doors, size 13 boots on the door step, etc.
Be a hard target and force the perps to move on to the next house.
Buy a dog.
Things like over penetration are a real concern if you have other people in the same structure. Knowing how much your defensive arm of choice penetrates standard structures is a very pertinent point of data. There is empirical data that shows that the platform that has the best compromise of "stopping power" (for lack of a better term) and low penetration in standard building material is the intermediate power rifle cartridge with a properly selected expanding or fragmenting bullet.
For example a .223 rifle loaded with some of Hornady's or Winchester's various polymer tipped projectiles penetrates walls less than 9mm or even #00 buckshot while still delivering superb terminal effects in gel tests. Small and fast projectiles have a tendency to dump all their energy in the first thing they hit. If that is a bad guy, well sucks to be them. If that is a wall, then stuff behind it is going to be mostly safe.
If you have family/neighbors I highly recommend you check out some of the various wall penetration tests out there and see if getting a nice intermediate power rifle like an AR-15 as your primary home defense arm. The platform has tons of advantages over more "traditional" style defensive arm like the 12 gauge or the nightstand pistol. There may indeed be other reason why such a platform is not right for you, but it would be worth exploring in detail why that is so you can understand those reason in detail.