Our first line of defense is a very noise Cocker/Springer cross named Ruger, who sleeps with us. We live out of town a ways, and Ruger alarms at the slightest sound he doesn't recognize.
Our second line of defense is the cocked and locked, Smith 1911, .45 ACP on the shelf in the bottom the nightstand on my side of the bed. I've been around 1911s for so long that operating one is second nature. And as far as keeping a loaded 1911 where kids can get at it, I can't even remember the last time there was a child in our house. Our grandchildren are all in their late teens now. Besides, they've all been taught since they were knee-high that they're welcome to handle and even shoot grandma's and grandpa's guns as long as one of us is supervising.
I guess our third line of defense would have to be the 20gauge (youth model) my wife keeps loaded, but with an empty chamber, in her side of the closet.