1. Home security system.
2. Shotgun.
3. Large dog.
Ditto! But, things to remember:
1 If the dog is well trained, let it have the run of the house at night. My wife was putting her in a kennel
2 My wife has a CCW and a great shot, but she knows not to go hunt down the source of the noise. They could be waiting for her. Grab the gun, kids, and cell phone and call 911. I recommend a cell phone (no cords to unplug or cut).
For some reason, I ended up with a lot of friends that went into law enforcement. All of their wives have CCW's and shoot regularly.