I know this thread is a bit old. And I realize this is my first post, coupled with my relatively young age (22) makes me not the most trusted source. However I saw that no one once mentioned the Kahr MK9. From my experience it's been an incredibly reliable pistol. In 2,000 rounds through the little guy I've only had two rounds that failed to fire. I attribute this to being when I first started hand loading and not so much the gun itself. It's a nice tiny gun with a 3" barrel. Very compact and easily concealed.
Like I said I'm fairly young, but having grown up in Vermont I've been shooting firearms for 12 years, which doesn't compare to most, but gives me some experience. When I first turned 21 and had my handguns legally transferred over to me from my father I originally carred a P226. Which is a great pistol, I would highly recommend anyone in the market for a new pistol to pick one up. Durable, reliable, and consistently accurate. However it is a bit large, and unless you're in an area where a jacket won't smother you to death it leaves a lot to be desired for personal carry. Which led me to grab my Kahr, which I was initially skeptical of. I've never been one for small handguns, it took me a long time to get around to picking up a 9mm because I was born and raised on .45acp (which led me to the .357, .41 magnum, .44 magnum and finally a .454...no .500 yet), so stepping down to a 9mm took some self-convincing. For awhile before picking up my MK9 I carried around an old S&W Compact I inherited, but the design of revolvers makes them a little bit bulkier than auto-loaders.
So with that said, I'll get down to why I'd suggest trying out a MK9. It's one of the smallest 9mm (or there are .40 variants if I recall) on the market that will fling lead down the range consistently and accurately. I have no issues at 20-25 yards quickly letting lose all 7 rounds. Not all together a great distance, but for a small compact pistol I think that is more than acceptable. And to be honest I don't see a situation requiring me to shoot in self-defense that far. I've already mentioned it's slim and highly concealable. I have fairly large hands and do not find it uncomfortable to shoot and the recoil is more than manageable, but this may be because I've been shooting magnums since I was 13, it's all pretty much reflex now. The pistol is not made of polymer, which I really like, it has a decent heft to it but unloaded is only 21 ounces (or so). The only real downside is that the clip only holds 6 rounds, with 1 in the chamber. They make extended clips, but that really defeats the purpose of a concealed weapon.
As others have said though, more important that the weapon you choose is the amount of dedication you put into becoming proficient with it. The best handgun in the world won't do you a lick of good if you can't quickly and accurately get off the necessary rounds. Also knowing when and where to use it is of equal importance. I was mugged once by a man with a knife. He was close enough that he had the advantage, so I opted to hand over my wallet instead of risking losing my life because I couldn't draw fast enough. Once he had what he wanted he let me back up, with the distance advantage I drew my weapon and told him to get on the ground. Instead of listening he turn and ran, getting away with my wallet. I could not bring myself to shoot a man who no longer posed a direct threat, let alone someone fleeing. I know this doesn't put me in the best light, or having a concealed weapon permit. However I think it's best to think about these scenario's realistically,