The Boomstick.
An NEF "Pardner" single shot 12 gauge with the barrel cut down to 20", and a big rubber recoil pad installed over the stock (after I put a few rounds of 3" magnum slugs through it, and lost use of my left shoulder for a week). Loaded with one round of Federal Low-Recoil 00 buck, with more available.
Not very tactical, I guess, but I like to play with my other guns. Take them out, hold them, take them apart, dry fire, etc. The NEF just stays taped to the back of my dresser. I can leave it loaded indefinately since the hammer isn't cocked.
I don't believe there's been a breaking-and-entering in my neighborhood in the last 20 years. (The houses are small, the people aren't rich...everybody has a hunting shotgun, prettymuch...not exactly prime robbery material.) My biggest concern is, I don't know, having a rabid dog or something in the street threatening kids. But, if the need arises, the shotgun will work on two-legged critters just as well, I should think.