If you were to pick a single handgun for Home Defense, Concealed Carry and Hunting, what would it be?
I'm going to re-answer in the spirit of the question. Since I don't hunt, I'll assume I'm advising someone new to handguns who doesn't have the budget to buy several guns right off but will probably buy more later (or has a wife/husband who will only allow one gun in the house) but wants the gun to be appropriate for as many uses as possible.
I'd suggest a 4" medium frame .357mag revolver, preferably the re-introduced S&W 66, and here is why...
For home defense a .38spl revolver is a terrific choice. Of course, a .357mag can fire .38spl. The 4" barrel gives more practical accuracy than a snub.
For carry, a 4" barrel medium frame revolver may not be ideal, but in an IWB holster it will work. I'd normally prefer an L-frame for the extra round of the 686 Plus, but without other guns to choose from for different situations, shrinking it as much as possible would be idea.
So, why not the 2.75" 66, a prior generation 2.5" or 3", or a 2.5" or 3" L-frame? Because now hunting is in the picture. The extra 1-1.5" of barrel in the 4" barrel will give needed velocity when hunting bigger game, and needed practical (quick) accuracy when hunting smaller game. I'd go .357mag because with heavy loads you can hunt most N.A. large game with it (though some state laws may be in the way), and with downloaded .38spl 148gr wadcutters you can still hunt the smallest of game.
All in all, it is just the most versatile of platforms for a one gun for everything gun. If you were to hunt but only small game I'd go to a 2.5-3" revolver (better for carry), if only large game then I'd switch to the .44mag L-frame S&W 69 or .44mag Taurus Tracker loaded with .44spl for carry and HD and magnums for hunting (more effective for large game, and legal in all states). But with the variety of different loads that can reliably work, a revolver is the most versatile for a one gun for everything gun if you hunt.