I finally decided on #4 Buck and re-stuffed the chambers today.  Yeah I know bigger is always better but went the 4 Buck route after doing some reading and conferring.

I bet the consensus will be OO Buck,

Anybody out there agree with my choice?

use whatever you like....

....I prefer 5 deer slugs

The 12 gauge shotgun has several primary advantages as a basic home defender.

First being, the sound of the action cycling into battery... it is unmistakeable, and will often turn away opportunists.

Second- directivity - lack of necessity to aim... particularly if you're using a shorter barrel cylinder-bore, you don't need to be precise to make contact

Third - muzzle energy.  There is no rifle or handgun that has as much muzzle energy as a 12 gauge shotgun.  It won't present the highest velocity, and the energy will be distributed across separated projectiles, but the net energy is still far greater overall.

Fourth - control - being a longarm, it is not nearly as easy to redirect or turn a shotgun onto it's operator.  A pistol is rather easy once a contestant is within arm's reach.

Fifth - Limitation.  A shotgun's projectiles can be sized small enough so that, while they may pass through a wall, will have lost significant energy in the front and back layers, to prevent them  from being nearly as dangerous to lives and property on the opposite side, while still being very effective on the FRONT side.

#4 is nothing to snort at.  000 buckshot may be bigger and heavier, but it doesn't take a big pellet to be effective.  More often than not, a similar charge weight with smaller projectiles will hit hard enough to send a target backwards enough to disable it, even if there's body-armor in place- that muzzle energy is doing the job.

#4 is a good general-purpose load, it will be equally effective on small or large, ground or avian, and it will relieve tires, radiators, and glazing of vehicles.  If one doesn't feel it sufficient, I recommend loading a deer slug first, then some 000 buck, then #4 shot, then rock salt, and a bird bomb (if you can still find one).  When an emergency circumstance arises, either reject or rapidly discharge the rounds you feel unnecessary, to get to the one you'll need.  The act of flinging out the flash-bang, rock salt, and birdshot will be a significant attention-getter before the heavies come to visit.

The mere appearance of antiquated barbarism will frequently convince a miscreant of unwise ventures.  Crossbows, compounds, and longbows work... but stepping out the door with a 28-oz framing hammer tends to incite self-defication.  If you're well exercised with the casual pastime of throwing axes, a quick flick of that hammer will prove deadly. 

If it's a close-range contest, a quarterstaff will disarm, cripple, blind, paralyze, dispatch, or all of the above, in quick succession.

Just don't run while playing Bagpipes-  you might get kilt.