Intersting talk about stopping power. The most important factor in my opinion is placement. Having been shot, and stopped, before when I was about 20 years old in an accidental shooting by a 22lr Colt Frontier that was dropped, by me

. When I dropped the gun it landed on the hammer first, which was resting on a live round. The round entered the inside of my left thigh, (missing my family jewels by about an inch) and stopped just before exiting my left hip, right below my belt line. On it's way through my leg it struck a nerve and a tendon, which flexed my leg like a spring sraight up in front of me knocking me on my butt. Yes, if I was in a state of mind and was determined to harm someone, I probably could have continued to attack, but, I was in fear for my life at the time not knowing yet where the bullet went and just the shock of "hey, I've been shot!" kept me still.
That was a big learning lesson for me and I find it interesting, other peoples oppinions on "stopping power." There are a lot of variables in the equation.