Same here in Virginia and probably most states. My understanding from the CCW legal trainer (5 years ago) was that the DA is either to charge with 2nd degree homocide or to press no charges at all. There is no "right to self defense" in any Virginia statute.
If one has the misfortune to prosecuted for defending the household - or sued by a wounded perp in civil court (whoops, that shouldn't happen) - IMO it's important to recognize that the firearm itself will also be on trial. So you want it to be a generic, plain-Jane model and not a Darth Vader "tactical" combat shotgun or a 50 cal Desert Eagle. A generic hunting shotgun and a conventional 38 or 357 pistol are far less likely to make you (the defendant) look like a kooky gun nut who was just looking for trouble.
Just my opinion.
Very dependent on which state. In NY and MA you're toast if you defend yourself. GA, FL, and TX you will PROBABLY be OK. Dunno about the rest.
There was an incident up here last year where a homeowner killed a guy who broke into his house, totally legit, but he had a bad time because of a stupid bumper sticker on his truck, something about shooting first and asking questions later (I wish I could remember exactly).
Mouthing off about killing perps is bad preparation for your trial, if you ever have to actually do it.