Last year for HD I bought a Baikal (Russian) 12 ga. Double barrel Coach Shotgun for $220. Main reason I got this was the price and I just like doubles, especially Coach guns w/20" barrels. I added a 5 shot buttstock shell holder, refinished the stock, and it now looks totally COOL! Loaded with 00 Buckshot, it rests by my headboard ready for use. On the nightstand is either my 9 MM or LCP 380. On the wife's nightstand is a SP101 .357. At the foot of the bed is our 90 lb. pitbull. What am I afraid of? Not much.
Now, I agree, the majority likes pump shotguns for Home Defense, and the 870 or Mossberg 500 would be good choices. Some like single shots. Some like semi-autos.
Point is, get what YOU LIKE in either 12 or 20 ga. and it should serve you well. A shotgun is the best weapon going for HD, but anything is better than nothing. Go to your LGS and check out the eye candy. If one gets your attention, handle it, ask questions about it, and I guarantee you will find one that grabs you.
Good luck on your hunt and stay safe.
BTW, welcome to the forum.