Coming in late to this thread but here's my 2 cents:
I began shooting when I was about seven years old (Dad and Grandfather trained me on bolt-action rifles and shotguns first). At age 9, my father gave me my first rifle and shotgun. At age ten, my Dad trained me on my first pistol (.22LR "six-shooter" single-action) first with targets, then quick-draw from a western holster.
During eight years in the Military, I had the opportunity to train with both the Colt .45 and the Beretta 9mm. I have over the years owned various Beretta, S&W, Glock, Sig et al. makes of pistols (revolver and semi-auto) in various calibers. I have settled on the 9mm as the best self-defense weapon for various reasons. In target shooting, I am ore acurate with a properly tuned .45, but in self-defense/combat shooting, I find that I can deliver from holster to first-round on target better with the 9mm. I also find it easier to return to target more consistently with the 9mm. And, in my opinion, combat situations are most often decided with first-shot kills, and the ability to finish a target with a rapid safety tap or two.
Now my performance with the 9mm is qualified however by the fact that I have made it a point to TRAIN myself on a specific weapon, regularly, and in many situations (you NEVER get to make optimal shots when it counts.... something is always "wrong".... racing heart, extreme noise, low-light, multiple targets, targets returning fire, etc...) You MUST train under the circumstances that you may be called upon to perform in.
The weapon you choose must also FIT you.... For instance, I have relatively small hands, thus a Glock with a 15 round clip is NOT a natural fit in my hand. I HAVE become proficient with one, but a S&W or Sig tuned, and with custom grips, radically increased my time to target and percentage of first-round take-downs.
Ammunition should also FIT.... I agree with Russ, all self-defense weapons should be loaded with hollow-points (and the weapon you choose to feed them to should be able to eat them all day without a single mis-feed). I use a custom load, designed for maximum expansion balanced with a higher probability that the round will not over-penetrate. In close quarters, it's much preferred to leave the round in the target rather than putting it through a wall (or bystander) after passing through tthe intended target.
Finally, TRAIN.... have I said this enough times yet? TRAIN, TRAIN, TRAIN.... You must know EVERYTHING about the weapon you carry/use. You should be able to disassemble and assemble the weapon properly, efficiently, quickly, and BLINDFOLDED. Be able to function check the weapon without thought. Be able to clear malfunctions as a matter of course, and in the dark. The weapon should be a natural extension of your body when drawn/fired. Learn, Know, and Live safety....
Never treat your weapon with less respect than it deserves. It's not a toy, a novelty, a show-n-tell piece, or anything else. It's a weapon.... a tool designed for ONE purpose... to kill, period. Don't advertise that you have it, don't show it off.
Never draw your weapon unless you are prepared to use it. And if you HAVE to use it, use it well. Don't shoot to wound..... ever. You are never that good. If you have allowed yourself to get in a position where it is necessary to fire your weapon, you are out of options. Kill the target, without hesitation, without passion, without remorse. Question and emotion should have already been dealt with BEFORE you pick the weapon up the first time.
Wow.... didn't mean to be so long-winded, but as my handle suggests... I am Opinionated.
