For tactical, and home defense use I'm currently running these 2 Mossberg's. One is a 500 "Combo Gun" that came with 2 barrels. The one shown is the 18" cylinder barrel, and the other is a 28" vented rib barrel choked with a Modified fixed choke. The other is a Mossberg 590 A-1 Mil-Spec that I just purchased last month.
Both are excellent shotguns for the price, and perform really well. The 590 A-1 Mil-Spec comes with a 9 shot capacity and a bayonet lug, along with a heavy walled barrel and a metal trigger group and safety switch. The gun is built like a tank, and functions flawlessly. For home defense I doubt you could not only find a better shotgun for the money, but find a better one period.