Quote from LEAPup:
I'd rather be tried by 12 than carried by 6...
Boxer, you should check into a Mossberg M590 (has the military spec action-I have one, and love it!), or Remington 870 with 18" barrel.
After you get the 12G shotgun (either 20" or 18"), you'll want to go to Brownelles web site and look into the recoil reducing folding stock. It's about $110, but WELL worth it!
With that set up you'll have a semi-tactical shotgun that will fit in very tight spots until you're ready to slap oped the folding stock, and chamber a round. you'll want to buy 3" magnum OO buckshot rounds, NOT slugs or birdshot.
Now if you want to get really fancy, get a new foregrip that takes a tactical led flashlight mount. You get this set up and you'll be in good shape!
Again, Remington 870express magnum, or Mossberg M590 with recoil reducing folding/collapsable stock should be about $600 all together.
If you've got more $$ to spend go to the wilson's combat website and check out their tactical shotguns. If you want one, have a friend or family member NOT in ny city buy it through an FFL dealer, and take it home with you turn-key, and ready to go! (No, I can't help with this as I'm a Police Officer part-time, and cannot break the law even as dumb as it is in NY.) I WILL, however, give you advice as I can assure you the police CANNOT protect you in an instant during a life and death situation. Additionally, I'll point to the above: I'd rather be tried by 12 than carried by 6 anyday! Get your shotgun, don't do anything stupid with it, and sleep well knowing you can actually defend yourself.
Semper Fi