Well am a little late to the thread but here is my analysis based on what I consider likely SHTF requirements:
1) Firearms should be extremely solid and as close to maintenance free as possible
2) As few small parts as possible
3) Fire a common caliber that can reliably take down game and a man but not recoil so bad as to make practice difficult.
4) The Ammo should be cheap enough to stack deep pre SHTF.
5) Must be Accurate: Since ammo will be at a premium in SHTF it must be accurate so you don't waste precious ammo!
Expect Ammo to be even more at a premium than now!
One handgun system meets all these requirements , a 357 magnum revolver.
It meets or exceeds all those requirements with the bonus that you can also shoot cheaper 38 spc AND a revolver is MUCH more tolerant to poorly done reloads such as may be available in a TEOTWAWKI.
Its more tolerant to overpressure (harder to break, nearly just one chunk of steel) and more tolerant of underpressure as well, as it is your finger and not the charge, chambering the next round.
A revolver will generally be more accurate as well, this due to fixed non moving barrel, no moving slide, more weight up front.
So if you are up against a man with a 9mm or similair autoloader and all other things are equal (skill, ammo quality, price class of gun) he will be in your range before you are in his and the fight is yours.
Huge magazine capacities while nice, will not be nearly as useful as the other requirements listed above.
This is because as history has shown a real SHTF is not likely going to involve a lot of James Bond-esque fights against overwhelming odds of Dr No's henchmen.
SHTF will dominated by resources shortages and that very much includes ammo.
The ability of a.357 Mag revolver to shoot "off" and low quality loads, and anextra caliber (38 spc) and be economical in their use due to better inherent accuracy is a winner.
Like everybody else, I agree a autoloader like a 1911 or a SIG is cooler and sexier than any revolver.
But a rational examination of likely SHTF requirements overwhelmingly points to a .357 Mag Revolver.
I like the famously indestructible GP100's (built on a 41 Mag thickness frame they often shoot HOT loads that have nearly the energy of a 44 Mag with no ill effect)
Also the modern 4 inch barrel on a GP 100 or S&W 686 is as accurate as the a 6 inch barrels on the previous generation of 60's revolvers.
In other words, yes, you can hunt with the handy 4 inch barrel.
Also unlike some Smith and Colt revolvers the little "hand" (forgot the proper nomenclature) that moves the cylinder is not a wear item. As a result they dont need regular retiming.
The common "counter" argument : "But, but, the military and police use only autoloaders so they must be "better" !" means nothing as they are in a completely different requirements set (pre-SHTF + generous logistics support)
Here are some pics