States have significant control over the types of people who can purchase, manufacture, and possess firearms. They are in integral part of the country's overall stance on gun regulation.
As with anything else, some states are more farsighted than others, but saying exactly which states are doing things right is hard. Of course, if one thinks that gun regulation is good and can work, than those states with the most gun regulations will appear to be enlightened. For this crowd, California is the holy land. It has by far the most stringent gun control laws. On the other hand, if one believes that guns deter crime, than Arizona is the place to go. In that state, there's nothing you can't do with a gun.
If you think gun regulation is good, good, good, then the best five states are:
2. New Jersey
On the other hand, if you think that gun regulation makes it harder for law-abiding citizens to defend themselves, then you would see the top five states as:
The full list is here and it's interesting to look at. For one thing, most of the states with relaxed gun laws have very high gun deaths per capita. States with strict regulation, as a rule, have a very low rate. However, there are exceptions that should give pause to everyone in the gun control debate. Vermont and Maine have very relaxed gun control laws, but have below average gun deaths per capita, in line with the rest of the northeast. Pennsylvania on the other hand has fairly strict gun laws but has greater than average gun deaths.
Of course, anyone with knowledge of statistics knows that these sorts of numbers are almost useless because they abstract away from the more complex relationships that social scientists study such as proximity to high gun supply states as well as the fact that gun control laws may be responses to higher than average ambient gun violence rates. Arizona has relaxed gun control laws and a high death rate, but it might be that Arizona is just a really dangerous place (being on the border and all) and that the fact that people are allowed to own guns makes it safer.
A more nuanced ranking of states would go into state compliance with basic permitting laws. Here is a provisional, better list of the states with bad gun control laws, though I don't know how to rank them.
Arizona. Arizona does not regulate ammunition or require background checks for private firearm sales. Again, as Arizona is on the border, it seems that it would be wise to allow law-abiding citizens to have guns, but at least to make sure it is citizens who are the ones buying and selling. Arizona is behind the national average in terms of submitting records of mentally ill people to the federal NICS database (see this fantastic report), which is designed to deny guns to those who are deemed mentally ill. Reporting to this database might have prevented the Virginia Tech shooting and may have also prevented Jared Loughner from obtaining the gun he used to shoot Gabrielle Giffords. To be fair, Arizona is better than other states on some other specific mental health aspects of gun regulation.
Idaho. Idaho is also very relaxed about gun possession. In itself, not a problem, but they have the same mental health problems as Arizona. This article details how the NRA has advocated for laws that guts commonsense safeguards against mentally ill people obtaining guns in the state. Idaho has also not submitted a single mental health record to the national database. To my mind this puts everyone in danger, because those people might leave Idaho and purchase a gun and commit a crime somewhere else. C'mon Idaho.
On the bright side, there is Texas. I'm from Texas, so I'll take a moment to praise it shamelessly. Texas isn't the best state for gun control, but it scores really well on a lot of metrics. It reports an above average number of mental health records and its rate of change is among the highest in the past two years. Texas also has provisions for a host of specific mental health scenarios and has a middle-of-the-road gun regulation system.
*Note: the photo for this article is a massive gun billboard I passed a thousand times while driving in Boston. For a while I didn't know what to make of it, until I realized it was sarcastic commentary in a state with VERY strict gun control laws. It reads "No ID required. No background checks. Criminals and terrorists welcome!"