Every person who has ever fired a weapon...... never fired one before.

One of the better rounds for all-around stopping power, recoil control, and availability is the .40 caliber. It may or may not be the best, but that's not the point. It's a good caliber for self-defense.

Firing warning shots brings to mind a thing or two:
- where does this warning shot go?
- if a life is not in imminent danger, why is there a need to fire the weapon at all? To scare.....?
- at the moment in time the trigger is pulled, it should be a situation where there is no recourse but to "stop" the threat (there. I said it).

In auots, I've owned a Browning and Beretta, and currently own a SIG and H&K. Of them all, I like the H&K .40 a tad better than the SIG 9mm, though I like the .40 cal round considerably more.

Whatever weapon you choose, it would be wise to try (more than once) several models and several calibers as has been suggested, thereby making your choice the best you can make it.