It would definately be easier to disarm a long gun from you. It's all in the leverage, try with a friend holding a stick in towards the middle with the end in your shoulder, as if it were long gun, and have your buddy grab the far end and see who has more control over it. If you were to fire in such a situation, off into wherever the barrel should be pointed, you risk shooting through (esp with a carbine) and potentially wounding a loved one/neighbor.
A pistol, on the other hand, you would both have about equal leverage. And because on this, your wrist being straight on the pistol grip would give you an advantage to their's being angled to hold onto the straight barrel, and would be worlds easier to get it pointed at them with such a short barrel.
It would be a difficult decision, against a pistol grip shotgun to a pistol. The shotgun definately has more power, but as mentioned before you limit your being able to open doors/manipulate any objects.
I also think if you're close enough, it'd be a lot easier to pistol whip someone and then get your barrel trained back on them then taking the stock from your shoulder and stroking them with it.
A carbine length rifle is still long enough from the shoulder to make going up stairs or turning around with it MUCH slower to manipulate than with a pistol.
Point blank, esp close enough to grab you, the gains in accuracy from a rifle aren't as significant as they would otherwise be.
I will aggree whole heartedly that one 00 Buckshot round would put them down harder than probably several 9mm's, but if you are in the home and proficient with your weapon should you have to shoot you should be able to dump your clip into them relatively fast and hit most of your shots. While still not as effective, for me to think of getting a chest full of HP's from even a 9mm much less a .45 will suffice.
In consideration to adrenaline, disassociative drugs, or the psychological/physiological factors that would stop them from feeling the pain or keep them going, those would of course apply to the long guns aswell.
Mind you, this is speaking only in terms of having to confront an assailant. If you feel you've got a positive identification of an intruder, you'd be best to call the police. It could a family member in the kitchen, it could be the dog getting up, which is why it makes sense to listen and stay put if you can. But in situations where it's worth the risk (i.e. kids etc) to investigate this is just my two cents. The gains of a shotgun increase if you believe there are multiple attackers also. Usually, thiefs don't try to rob houses they beleive are occupied at that time. If they've stumbled into a poor situation they are more likely to flee, and if they stick around their intentions are probably to kill you for something you did/they think you did, or to kill you objectively to evade capture. Most the fellas breaking into houses aren't the smartest bunch in the first place, but then in turn may have done this kind of thing before. Weigh the odds, and act accordingly. A lot of people think a gun in their hand makes them a pro, speaking more in terms of the bad guys, and if you aren't confident with you ability with said weapon you should not be using it in any sort of confrontation. You and your loved ones safety is top priority, which is why I also would not advise proceeding in the dark for the home-turf advantage as you would not be able to properly identify the individual or threat he poses, say whether he was armed or not and with what.