I once read something on this forum. I have no idea who said it, but it was something along the lines of the handgun in your nightstand is there to get you to the shotgun in your closet.
I fully stand behind the idea that if you're going to own only one HD gun, that handgun in your nightstand is the one it should be. After all, a shotgun in the closet doesn't do you a bit of good if it isn't accessible.
That said, I keep a box of 00 buckshot in the closet next to my bird gun (in the closet). Sure the 28" barrel is horrible clumsy through doorways. And sure, the action lock on it inside of the case it's in will slow me down. As will the empty mag.
But, anything is better than nothing.
I'd say if you have to own a HD shotgun, it should be short enough to fit sideways through doors (with you holding it), you should be practiced enough with it to do the job when you're scared enough to soil yourself, and it should be powerful enough to get the job done.
But I still maintain that, for HD, a .22 in the nightstand is going to end up being more powerful than a 12ga in the closet.
I also maintain that the sound of a pump is the single most intimidating sound in the world.
Really, the only important thing is that you can hit what you want to hit. It doesn't matter if an invader gets hit with 10ga buckshot or .410 birdshot. Either is going to make him seriously reconsider whatever he was doing.
Practice, practice, practice. When push comes to shove, that's what's important.