For self defense purposes, I prefer 9mm for the typical pro-9 reasons.
For open carry to protect against especially nasty 4 legged critters, 9mm < .40 S&W < 10mm.
If you want a CZ style pistol for this purpose, look up the EAA Witness in 10mm. It's a well built, inexpensive CZ clone.
Currently Own: Beretta PX4 9mm, Glock 23 (Gen 4), Glock 19 (Gen 4) x2