Here in Florida we have stand your ground and the castle doctrine. If you are put in fear of your life you can use deadly force. If an intruder enters you home you can kill them....period. Happens almost every day here, no charges filed.
Here in NJ you can use deadly force if you are a cop and there are no witnesses with videocams. Otherwise, they convene a grand jury in the great majority of cases, obtain search warrants, ransack your house and impound your car, classifying the lug wrench as a deadly weapon. This thoughtful kind of mild treatment is only in cases where it was obvious self-defence.
I disagree with those who think only massive killer rounds will stop an intruder, as if all of them were Viking Berserkers. My semi-non lethal .38 'snakekiller' birdshot rounds make a mighty BAM and a bright flash, inflicting great pain if aimed properly. This alone will cause most thieves to flee immediately.
Using spears or bangsticks may result in having them taken away and used on you.
The other issue is that no one has suggested inviting the intruder to sit and chat, maybe share some leftovers and chips, watch the game, have a couple of brewskis and some laughs. You know. Like Jesus might have done.