"I am planning on getting a firearm with the correct training that will be stashed away in a crawl space, never to be used unless a dire situation arises."
That parameter sort of narrows down the options. Without going into a whole new WTSHTF thread, the ghost ring pump can be very effective out to 25-35 yds., and even a bit beyond. Consider what that 100 ft cone encompasses. For self defense in urban/uburban environs( protecting one's home) it pretty well covers the distance across the street to the next house without going through the neighbors house. Pretty much the same if shooting from second story window. Unless one's house has a flat roof, like the LA Korean shops, most house having pitched roofs are not good fighting positions I would think. And the scenes that I saw of the LA riots, the Korean shooters were on 2nd story roofs (if even that) shooting primarily at direct threats to their stores( looters or molotov cocktailistas) and not leaving their positions to hunt vermin. Once you move out, you've lost cover and concealment as well the high ground for observation.
That said, a broader variety of social tools is the way to go, IF, and only if one is prepared to train properly and maintain proficiency through periodic practice. The almost forgotten pump shotgun in the crawl space scenario aint' a pretty one, but any long arm is better than a mere handgun. My Mossberg handles nicely and can be brought to bear on multiple targets quickly with the ghost rings if necessary til I can get to the quad .50's in the cupola...;>)
Thanks for the comments. I'll remain neutral on them because I know there will be others that prefer the shotgun. I'm not opposed to them and do think they make a great third option. I think you see them as a perferable first or second, and in some cases I might agree.