Voted the fourth option, considered the 5th, but nah, because I'm quite cool with hunting rifles and the likes.
Don't see any really good reason for handguns to be legal. Having one to defend yourself from crime provably does more harm than good (the chance of you warding off a criminal is exceeded by the chance of you accidentally firing on yourself, having your kids steal the thing and get hurt, or causing a criminal to use greater force in response to your threat), and even if it didn't, it would be worth banning them to keep them out of the hands of criminals. It's no real secret that the US has way more issue with gun crime than almost any other country, and gun crime sucks because, well, it kills people where other weapons don't.
Yes, I'm aware the US already has fifty billion guns, but cracking down on them now is how you improve that number in the future. Not that anyone in politics seems to care about anything past 3-4 years or so, sadly.
EDIT: The fact that anyone could even consider assault weapons legal just baffles me. IT'S A WEAPON DESIGNED TO KILL LARGE NUMBERS OF PEOPLE AT ONCE. Unless you have some deluded vision of yourself singlehandedly killing a bunch of terrorists Jack Bauer-style, then there's just no reason for a civilian, non-criminal to own one of these things.
EDIT2: The point Jim raises about guns being as traceable as cars is good. If you must have firearms be legal because of a flawed consitutional amendment, then treat them as you do cars: something you have to show responsibility in order to operate. i.e. I see nothing wrong with demanding a gun-owner's license (and evidence of firearm training, similar to driver's ed) and for each gun owned to be documented in some sort of central registry. Some states have this, but to my understanding, not all.