.40 S&W
At the end of the day:
compared to 9mm, .40 S&W offers wider, heavier bullet with more energy
compared to .45ACP, .40 S&W offers better concealability, less recoil, more mag capacity
I own a 45 1911 but am considering the CZ 75B in .40 S&W. 9MM is a old, historic round with...