There may be some merit to the 9mm Vs 45acp debate. Personally I like a 45. It makes a bigger hole and the recoil is not bad. A 9mm makes a smaller hole and will not do as much damage as a 45 (but the depth of penetration may offset this). Any way, Shoot what you are comfortable with, like and most importantly own! There was a reason the saying "beware of the one gun man, he probably knows how to use it" came about.

Would I feel "underguned" with a 9mm? NOPE!