However, stating "there is a significant difference between the 9mm and the .45" is completely misleading. The differences in ballistics are like day and night. The 10mm is also a good choice for defensive rounds. All I can say about the 9mm is that it’s better than nothing and fairly cheap to shoot.
I know this thread isn't about ballistics, but I had to chime in on this one.
Also, if you have concerns about the stopping power of your defense weapons, might want to check this out. There are other similar round, this just happens to be one of my favorites: http://www.pmcammo.com/starfire.html . It’s all about delivering the energy to your target, not letting that energy pass right through the target.
It is a good thing that I did not say that, then.