Leadslinger - The case (in my mind) is simple for registration. Because guns are used in the commission of crimes, because guns can and are stolen from law abiding citizens, the government (we, the people) have the right to know to whom the guns belong. You are correct, a lot (my guess is the vast majority) of criminal guns are non-registered. A smaller subset of those are stolen. That is why I make a simple proposal:

Automatic 5 yr. non-parole eligible sentence for a felony committed with a handgun (registered).
Automatic 10 yr. non-parole eligible sentence for a felony committed with an unregistered or stolen handgun.
BTW - both crimes (the original felony and the gun portion) would be classified as strikes under the three strikes law.
Automatic 5 yr. non-parole eligible sentence for possession of a non-registered or stolen handgun, even if not used in the commission of a crime. Also a strike.

My goal is to not confiscate guns from law abiding citizens. As I said before, I have lived in a country (New Zealand) where handgun ownership was illegal. It certainly changes the climate. In the US, there are already too many guns out there to make such an approach work. However, using the sentencing guidelines above, there would be a very harsh penalty for those criminals who choose to use a gun and for those criminals who steal a gun. I believe that deterrence would occur with this kind of approach. Somebody earlier said that we can't legislate morality. That is true, however, the state (we, the people again) has the right and the duty to reward appropriate behavior and punish inappropriate behavior. Unless you want to live in anarchy, we have chosen to live in a nation governed by laws. I am still interested in hearing from the folks that support gun rights, what impact would these laws would have upon you if you are a law abiding owner of guns...