Couple things I'm surprised no one has mentioned.
A good bright flashlight is an excellent tool to have, aids in target ID, blinds the bad guy etc.
All cell phones, by law, will dial 911 even if not on a service plan. Old cells can generally be had for free on Craig's List or Freecycle. Plug in charger, put cell on nightstand. I'd get a couple, were it me.
I am amused by all the internet wanna-be Rambos who'll shoot the first shadowy figure they see moving in their home. Let's hope it's not your spouse coming back from a midnight snack, your kid's boyfriend/girlfriend they've snuck in, your kid sneaking in, your kid's friend they had over to hang out etc. If you really think the person in your house can index on your voice, aim and fire faster than you can pull the trigger of the gun you have at the ready well.... either your reflexes are very poor or you're getting invaded by one of the plague of ninja assassins people on gun boards always seem to be bothered by. And all that assumes the bad guy is stalking your house with gun in hand and at the ready, which is very uncommon outside of actual home invasions.
I wonder how many of the kill 'em all and let God sort 'em out types have ever actually killed someone, or seen a person die violently? I've found that tends to dull the bravado a bit.