I mostly rely on my location (the middle of nowhere) and the dogs as deterrents. Good exterior lights and a peephole usually let me identify what the dogs are after.
Beyond that, I keep a 30-30 in the closet by the door, and a handgun/flashlight/phone locked in my bedroom.
Incidentally - if anyone didn't know - you can use a deactivated cell to call 911, so if it's inconvenient to keep your actual phone in your "safe area", you can always just keep an old phone there instead.
si vis pacem para bellum