I'd consider a 3-gun combination.
A 12 gauge shotgun, preferably a Remington 870. Lots of parts available, very versatile. Accessory barrels means the same gun can switch from an 18.5" cylinder bore firing 00-buck in defensive situations to a rifled barrel with sights firing sabot slugs against game animals of all sorts to a 28" vent-rib style with chokes and some #4 or whatever for banging birds of all sorts. Hard to beat that kind of versatility. Down side - ammo is very bulky in terms of both size and weight.
A .22 rifle, preferably a semi-auto. Something effective against small game that won't require regular practice to become proficient, meaning it can be handed over to my wife or another neighbor or family member in a pinch and they will be able to deploy it effectively with only minor instruction. Down side - it's just a .22, meaning very careful shot placement in hunting situations especially if it's all you have left. Not the most effective defensive solution.
A pistol, of any sort if you DID have restricted as a choice. If you need to move locations without use of a vehicle and have a reason to carry for personal protection such as SHTF, just about any centerfire pistol will suffice. It can be easily concealed and the ammo can be carried in convenient magazines or speed loaders for fast charging. They are far more effective than a .22 in defensive situations. Down side - in a SHFT scenario it is likely that the registry would be used to confiscate all restricted/prohibited firearms at least, unless there was a complete collapse of government and social/law enforcement services. Also, not nearly as easy to use in hunting situations as a rifle or shotgun.
An Enfield is also a good choice, and I have been contemplating building a scout-like .303 on an old Parker hale should I find one. A couple 10-round mags and decent sights makes for excellent game-taking ability and extreme defensive capability. Lots of ammo kicking around in CT or wherever, and I already have a couple boxes of Federal grey-box (pretty sure the box is blue now!) set aside for practice and hunting use.