An SKS would make a decent defense gun. By the sounds of it, you want a universal "ranch gun". A couple things that I would consider, is capacity, length, ammunition, and sighting.
The first one is pretty easy to fix; while I think that for 90+% of bad social situations, ten rounds is probably enough, there is nothing that I would rather not do than reload when I should be shooting. Get the steel 30 round magazine. Its more durable than the plastic ones (especially in the cold) reliable, and drop right in, as soon as you take out the old one.
Length is a harder one, and because of the gas operation best left alone. But overall in certain house situations, it is about 8" too long in barrel length to be ideal in the house. Probably would not bother me, if I was not debating it on the webz, or unless I was putting together a list of ideal attributes.
Kind of mixing up the order here, but that brings me to sights. The front sight sticks up and is too easy to grab if someone got the opportunity. That's kind of a nit pick, but I'm speaking about the ideal; don't forget. And irons suck in the dark. A better choice would be a scope or a red dot sight. I put a scope on mine, not on the receiver where it will change the zero every time you take it down. A better choice for quicker acquisition would be a red dot or a reflex sight, mounted up front in a "scout rifle position". Though that may be a pain as well.
For ammo, there is not much in the way of selection. Most of it is corrosively primed FMJ. Be prepared to clean it lots. There is softpoint hunting ammunition from PMC, but I have never seen .312 varmint bullets yet.
