I live in a city with daily shootings, gangs, armed robberies, etc. but that activity is mostly in a different part of town. I don't carry obsessively as many do. I use good judgment and SA to avoid the scum, so the last-resort of deadly force is a minimized risk.

When I do carry, a 5-round revolver or a .380 is ok with me. I've never heard of a crime victim needing 18 rounds of 9mm to stop a violent felon, but it's theoretically possible. I'd carry my M&P FS9 if I really felt the need, but I just don't.