Most of the recommendations for a revolver are spot on. Since you said "handgun" I assume you have a reason for that opposed to a shotgun. Caliber for home defenses should at least be a .38 or larger. A .357 gives you options of shooting either .38 or .357. Although I have not shot the new .45/410 handguns, that may be a good compromise between a shotgun and handgun. Some of the new 410 loads for these revolvers are pretty impressive. I would not want to carry those huge chunks of metal on my hip, but for a night stand home defense gun weight is not that important. Try shooting it w/ the 410 and .45 and see how you like it.
Do not go with an auto loader unless you are willing to spend the time to be able to manipulate it, clear jams, change mags, etc under stress just as easy in pitch dark as in day light. Most people think more bullets is the answer and are dead wrong. The answer is reliability.... which is a revolver. Self defense auto loaders are only for those who spend enough time with them to be be tactically proficient under stress. At the risk of insulting all of the self proclaimed gun slingers, most of the non LE public does not train or train properly with an auto loader for self defense.