Thanks for that informative post, but if I were to get a firearm, I think I would go with a semi-automatic handgun loaded with snake shot. By far and away, the only think I'm likely to need to shoot is a snake.
A handgun would be less unwieldy for someone like me than a rifle. Any person I could ever see myself needing to shoot would be in the house. Snake shot is unlikely to kill anyone and is extremely unlikely to injure a non-target if I miss. Sure it probably won't stop a very determined attacker, but that is why I want a semi-automatic. I want neither range nor power. I want something light and usable by a poor marksman. I want to deter and frighten. If I'm going up against someone who knows what they are doing and is armed, then I've got no chance anyway.
But for the most part I'm one of those people who feel uncomfortable with firearms and is not at all comfortable with the fact that so many people in my state (Texas) have them. But accepting the Constitution is an all or nothing thing. It's not like the Bible where you pick and choose which bits to apply.