Since the OP asked what pistol: Springfield LWO with a Viridian C5 series laser/light.

Glock 17

I haven't seen one open up to 4 inches in the average room size distance. Both my 18 inch guns don't.

Yea I shot my 18" shotgun with #4 in it and within about 10-15 feet it punched one big hole around 1.5"-2". They don't open up very good. I'll see if I can find the pics.

This was actually duck loads I was shooting. The holes that are on the targets were from around 10-15 feet the slightly bigger ones were around 25 feet. Regardless I wouldn't want to be hit by it, but its not one of those things you just aim in the general direction and pull the trigger it doesn't spread enough at those distances. Might as well shoot slugs at them.

Yep, mine was the same way. I practiced at the length of my cabin, which is 24 feet and I was under 2 inches still. I am not arguing a shotgun is a great weapon, I just think its a poor home defense gun unless its auto and has a light. I can't fathom using a pump with no light and think its a good choice.

I do a ton of work with local cops and non of them even carry shotguns anymore. Its all pistols with lights, carbines with lights. Both weapons will rule the night.

Glock 17 with critical defense hornandy and a tlr1

Using Winchester Super X, 2 3/4", 9 pellet 00B, fired out of a Remington 870 Wingmaster through a barrel that had been cut down to 18 1/2", I get a spread of about 4" from 7 to 10 yards, which would be equal to a shot from down my hallway, into the living room. Not saying you don't have to aim, but I do get some spread. Even a 2" hole though is quite devastating.

I don't doubt this ^^^^^^^^^^^^

12 ga with 18 1/2 barrel and an xd9 subcompact stay beside the bed.

1911A1 and a streamlight. I trained with gun/light combo for years and it's what I use best. I never have liked the idea of a light mounted to my gun. Just can't take to it. My setup may not be the latest and greatest, but I'm willing to bet I can give a garden variety home-invading slug a run for his money. My wife is not to back me up and she knows it. Her job is to lock herself in the master bath off our bedroom with her .38spl and dial 911.

Kimber 1911 45 or Kimber Solo with Crimson Trace laser if it is dark.

Cz 75 bd

Springfield 1911 with laser sights that on my nightstand.

I usually have a cell phone and a lamp on my nightstand. I could probably throw one of them and take an intruder's head clean off...

That's my wife's job too.

The beast of course

What ever happens to be out of the safe at the time. Glock 27, AR, Sig 380, Shotgun, etc.

Same here. Also have an 870 for my wife because she feels comfortable with it. I wish my CZ had a light mount on it, thought about selling it and getting something different just for that reason but I love my CZ.

11 rounds of .44mag lever or 17rounds of .40XDM in a bedside holster. The lever goes hunting down, the Springfield waits for the locked bedroom door to jiggle or kick in.
I have strategically placed motion activated nightlights with different colored bulbs. None of which illuminate me, but allow me to know where they are by color. Eliminates the need for me to beacon my position with a gunlight or laser.

I always have a p238 with me, even when . No getting caught with my pants down.

My wife plays back up vocals with a Beretta .40cal.

This guy is more paranoid than me. And I thought I was bad.

FIFY

No, just tactics and preparedness.

I don't mount lights on my guns, except Mini-14 for coyote duty. The thought of pointing my gun to see who it is doesn't sit well with me, nor do I like being a beacon. I respond with a 1911, and a VERY bright light that I can, and do use independent of the gun.
I think most of us have a good basis for our defense. I pray that none will ever have to put it to use.
Paul