Right now, I rotate between 9mm and .45ACP. Although, given the overall size/weight of my .45, I do not find it very "accomodating" as a CCW. Rather, I find it more useful for HD duty. So, I generally prefer the 9mm (3.6" single stack). In the near future I will be looking in to the .40 S&W caliber (for CC) in that I feel it may offer a bit more "stopping power" vs. the 9mm.