It's not a new article, but I found this Guns & Ammo 2005 primer on home defense shotguns to be very helpful in describing the options available.

It's got little nuggets of wisdom, such as this passage:

What kind of barrel do you want on your fighting scattergun? First of all, you want as short a tube as possible. This is not because a short-barreled shotgun has any ballistic advantage but rather because it handles better in confined spaces like hallways. The legal minimum is 18 inches (as long as that length does not result in a gun with an overall length less than 26 inches). Many shotguns are currently made and sold with 18-inch barrels, so they aren't hard to find. You can have a shorter barrel if you live in a state that permits it, can qualify for the transfer and are willing to pay the $200 Federal Tax Stamp. I am sort of a shotgun nut, so I have a 14-inch 870 Remington, and I guarantee you that it handles much better than an almost identical gun with an 18-inch barrel.

[The Home Defense Shotgun - Guns & Ammo]