There are several good shotguns on the market today.
I'm a Remington 870 guy. Had on in the coast Guard, I have one today.
It's a war horse.
That being said it is not my go to firearm for home defense. A lot of guys on here are about to verbally kick my butt however a shotgun is not the best firearm for home defense. I used to have to sweep vessels wit this weapon (Rem 870) and it's long, and cumbersome for extremly tight quarters. A handgun is better IMHO.
My wife and I have a plan worked out if there is ever a break in. She grabs the shotgun and we both work our way to my childs room. Once there, I go find the threat. She blasts anyone coming in the childs door. It's a great last line in the sand gun.
To move through a home, a pistol with a light and maybe laser in my opinion is better. If you already have a reliable handgun, I can only give you a Remington 870 point of view. It neve fails, has incredible stopping power. And will intimidate any foe.
http://www.youtube.com/watch?v=NuW-eoDIGps
http://www.youtube.com/watch?v=o19uQDce7OQ
http://www.youtube.com/watch?v=hrxkjRXk7m8