9mm is a fine round
.40 S&W is a bit too snappy for my liking
.45 ACP is a fine round, it's what I carry every day
10mm is probably a bit much for CC, but would make a great sidearm in the wilderness
I don't carry .45 ACP because I think "oh its the biggest baddest round ever and will 1 stop any and everything!" I carry it because it is easy to control in my carry guns and I like the slower bullet for less chance of over-penetration. Besides, if I need more than 21 or 15 rounds (depending on what I have on me that day) of .45 ACP, I don't think I'm in a situation that 31 rounds of 9mm will solve. I'd rather have a long gun in my hands at that point