Which handgun would you recommend to someone with little or no firearms training or experience, for home protection?

I have a Taurus Judge. Save your money. Inaccurate in .45 LC, ineffective with .410. I won it in a raffle, so it sits in my safe. Buy yourself a Glock or a nice .357 magnum Ruger or S&W. You won't regret either one.

Glock 19. 9 mm, most common ammo, simple to use, accurate and reliable. Rack the slide, pull the trigger. Easiest. Goes bang every time. Thin walls? How about a safe and reliable 12 gauge Remington or Mossberg pump with buckshot. Won't shoot through the walls as easily. If you don't like the recoil, get reduced recoil buckshot, or buy a 20 gauge pump. All that being said, the only ammo available now is 9mm, 5.56/.223 and .308. It will cost you a buck and a quarter every shot, until the ammo shortages are rectifed. Nut much .357 or .38 spl available Me? I keep a 12 gauge in the bedroom and wisely stocked up long ago on ammo.

KSG makes a 12ga shotgun with twin tubes, collapsable stock, 23 round acpability on low brass, also optional door breaching barrel add. Like a Mossberg, but this is the KingKong of home defense. 15 each 3" high brass military 00 buck capacity. A little rough on momma, maybe.

I too would recommend a larger revolver for stopping force if it came down to pulling the trigger BUT and I emphasize this.....it's NOT a game....it's NOT a TV or video show. NO to having a handgun in the house for self protection BEFORE you talk to someone at a range or store to determine what handgun would be good for you, try it at a store range or range, get VERY familiarized with it. I recommend a cylinder handgun because they won't jam but I am familiar with both. You're not there to be in a war but to STOP an action with as few shots as necessary, therefor, the bigger the round, the faster the stop, lethal or not. Also, know that the round if not stopping the individual, can and will penetrate most walls and go through areas where you don't want them to go. Shotguns stop a wider range but the same thing, it goes wider than what you need usually....and KNOW HOW TO USE THOSE AS WELL. Harder to get to and more time to get to and use. GET TRAINING FIRST. Know how to maintain them. I learned how to use a shotgun at a very early age for hunting from my father. Rifles and pistol and other weapons through military on ranges and actual combat, then as a police officer. My home defense pistol is my 1911A1, mostly because that pistol is what I am most familiar with from the many years in the military but that's not what I carried while with the State Patrol years ago. I carried a revolver before they went to the semi-automatic 9mm. I'm not fighing a war in my house. I have hunting rifles, hunting shotguns, and my pistol and KNOW that any gun is LETHAL. It's not a game. KNOW what you need, KNOW how to use it and make sure other's in the house KNOW that it's not a toy.

Personally, I wouldn't recommend any kind of firearm, for self defense, to any person who hasn't had ANY weapons training at all. That would be almost as irresponsible as recommending a big bore liter sportbike to someone who just learned to ride a bicycle.....

Putting the cart before the horse.
Training first, then rent several to find the one you shoot best with... Then purchase and train a lot with it. When it can be pulled and have an accurate shot in 1.1 second, then you have the person protection that you needed.

A pump shotgun.

Hand gun any 9mm will do you good but for home protection get the mosberg 88 defender, it holds 3 more rounds than the 500

If you not very experienced with firearms and only intend to use it for home defense, get a 20GA pump shoot gun. The Mossberg is good and inexpensive. Having a pistol for home defense is not a good idea. If you intend to get serious about shooting then you can consider a pistol. A shotgun is easy to use and effective. I do recommend you take a home defense class and become very familiar with the laws in your state and city. Retired DEA SA and Retired Cdr. USNR.

Any slide action shotgun. You don't even have to fire it. Just the sound of the slide, will make most wrong doers go the other way.
Pistol? My Sig Sauer P226, has only jammed on me once in the 30 years I had it. Go with the P228, it has a manual safety (the P226 does not). P229 basically the same weapon, but chambered with a .40. Can be upgraded to the .357 mag with just a change of the barrel and spring. You just have to buy the special rounds.