Which handgun would I choose to take into combat, given my choice?
Hmm... Good question. There's any number of decent choices, but to pick just 1?
A CZ 75 would be one choice, tied with a BHP. I know that the plastic fantastics are nice, but I still want real metal when the chips are down.
But I wouldn't feel at all bad about carrying what I've got set aside for such purposes, should it come down to that. Flame suit on, but keep in mind that I trust it and I don't care if you do or not: my Taurus PT-92. So far, it has been just as reliable (100%) and accurate as the name brand kissing cousin combat pistol. It has proven itself to me. Why spend more when I won't have anything more to show for it?
Heck, I wouldn't even feel bad about carrying my ol' 4" 686, or for that matter SWMBO's ol' 4" Model 15. Either one of those would be ample as a combat sidearm. Either one is enough to reliably get the job done.
True, handguns don't win battles, but they just might save the live of the soldier who does. Handguns are for the times when you are not on the assault. When you are not "out on ops", but answering the call of nature. Or in your fart sack. Or in a hole in the ground in the middle of the night, and have to repel boarders at arms length, places where the rifle (even the short carbine) is to big an bulky.
Yep. They are darned useful when the other guy is trying to crawl into your hole with you. They are darned useful if you happen to be a crew served weapons gunner like I was (armed with a 1911 at the time) and don't even have a rifle. They just might let you live long enough to reach your rifle if it comes down to it, like if they catch you out taking care of, uh, "business" or other such activity. POL duty. Pitching cases of ammo off the back of the truck. Same thing, rations, or other supplies. There's any number of mundane things that soldiers have to do in semi-tactical, rear area situations where the rifle might not be right at hand.
In the real world, two points:
1) You don't get to take your personal sidearm, except in certain elite units.
2) Even in those, there are usually only a few models the guys go for, so ammunition and parts have at least some commonality.
While this is true, it really doesn't apply to me any more. My active duty military days are behind me. If I go to war now it will undoubtedly be as part of a militia, armed with whatever I happen to have on hand. If they issue me anything in that case, it'll most likely be just a rifle, or maybe a LAW or 2 (like the Germans did back in the latter days of WWII with the Panzerfaust). In that case, I'll be keeping my personal handgun, thank you.