Interesting and popular topic.
I am a dedicated bird hunter. Have been shooting and qualifying with various firearms since childhood. I often carry guns (typically shotguns) in my truck when traveling throughout the Western US.
Seems to me that you need to be very clear on a couple of things when considering a firearm for personal defense...
1. If you are threatened - seriously - how would you respond? It is always better to run from conflict rather than confront it. Can (would) you pull the trigger on someone who is threatening you?
2. Do you have any idea what would happen AFTER you pull the trigger? If you kill someone, you are likely in deep poop. If you simply wound them, you are likely in deep poop. Remember that determination of self defense is after the fact, subject to results of an investigation, and interpretation by law officers, District Attorneys, and Judges. There WILL be consequences.
3. If you are considering defense against animals, there are very few animals that will seriously threaten you. If they do, you are probably going to be in a sleeping bag, or waders, it may be dark, and the situation is going to be really stressful. A hand gun is not the best choice for this purpose, unless you are very well trained and practice a lot. A shotgun is much better - especially at close range.
4. State laws on possesion of firearms (as previously discussed) vary widely. If you are stopped and present probable cause you may be searched without giving permission. You may be found in violation and cited or arrested.
5. When you pick up a gun, the confrontation changes. You may be required to actually use it. Food for thought.
That said, there are good alternatives for firearms intended for self defense against people and animals. I have three short arms which I carry (or not) depending on the situation I expect to meet...
a .22 caliber stainless S&W kit gun. Very handy, rust proof, and good for use on camping and fishing trips. Excellent for snakes, and for potting grouse.
A Colt 1911 80 series Officer's Model in .45 ACP. This is a small carry gun, and I can hit with it out to about 25 yards. If I ever had to use it, I expect that it would be deployed at less than 10 feet.
A .44 Magnum S&W 629 Mountain Gun. This is a serious gun, and would likely turn most people/animals - provided they were actually hit. I have carried it in Alaska and the Western US. I do not carry it while actually hunting, since I have a shotgun in my hands, and that is a superior weapon.
My two cents.
Mike S