I prefer to keep things simple. My defensive gun when out on the land is a Mossberg Maverick 88. It is the 7+1 Security model with a 20" barrel. The only modification/accessorizing done to the gun is a tube-mounted flashlight and a 6-slot shell holder on the stock. I doubt that I have more than $250 invested in the gun, but I feel confident in its ability to get the job done.
I might have a fancier setup if we lived out there full-time. For now, it would seem almost wasteful to leave anything with too many fancy gadgets unattended on the land for the majority of the year. I frequently bring an AR or two out to the land with me, but these are for fun and varmint control more than specifically for defense.