That's a tough one! But overall I'd have to say my Kahr MK40, all stainless steel construction, the extra weight helps absorb recoil, large caliber, no external safeties, small flat size makes it easy to conceal unless you are stark naked. Otherwise, I'd probably go with a 1911 in particular my Detonics "Combat Master" .45 ACP all stainless no "mim" parts, can be completely dis-assembled with a minimum of tools or none, most parts are interchangeable with other 1911's, and the shortened grip frame makes it easier to conceal, especially with the addition of "slim" grip panels. On the revolver side I'd go with the S&W Model 640 .357 J-Frame all stainless, easy to conceal and shoot with .38 specials, .357 is another matter! But if needed the gun will handle it, maybe not the shooter! The smallest gun in the largest caliber that you can handle are my top priorities, I like the extra weight that all steel construction provides in these small handguns, they are easier to control and practice with, and their robust construction insures that they won't wear out that quickly. The concealability factor is also paramount if you can only have one gun, you're going to end up wanting or needing to carry it, under all kinds of weather conditions and it's pretty difficult to conceal a full size or intermediate size handgun under a T-Shirt or in ones pocket during the summer, especially where I am in the Southwest. Fortunately, at least for now we are not limited to one gun, although it may come to that, or no gun, at least not legally if certain politicians get their way. WE MUST NEVER LET THAT HAPPEN!!!