.45 ACP is definitely fun to shoot and I shoot a fair amount of it. The .45 can not be argued with for personal protection, but 9mm got my vote...
Most of my pistols are in 9mm. They are high capacity, balanced, reliable, accurate, economical to shoot, and designed around the bullett...
If the SHTF happens, outside of the .22 long rifle, I believe 9mm ammunition will be the most readily available. It's NATO and used by almost every Government around the world. It's my personal opinion that the 9mm will out live the .45ACP for this reason...
While moderate in recoil, 9mm is undoubtedly a renown man stopper. Women, children, small hands and large can all shoot the venerable 9mm...
Heck, even Wild Bill Hickok used this cailber (.36)... If it's good enough for him, it's good enough for me... :-D