Given appropriate attire, a guy can conceal a 12ga shotgun, but that doesn't make it a great choice.

I have holsters to conceal pretty much everything on that entire list, and I have on many occasions left the house with a Ruger SRH Alaskan or a full sized 1911 tucked strategically at the small of my back, but it's WAY less convenient than a micro-pistol.

I'm also a big fan of the LC9 for just a touch more stopping power. It's also a lot easier to shoot than the micro pistols like the LCP, just for the extra half inch of grip (less muzzle jump as well). The only down side is that somewhere between the LCP and the LC9 is the breaking point for "concealability". I can literally carry an LCP while jogging shirtless in nothing but gym-shorts with a draw string. Drop it in my pocket and it's no more visible than an Iphone. The LC9 is JUST big enough that the grip protrudes a little too much for a pocket gun, so I almost always carry it IWB SOB or FOH.

Variety is the spice of life, and obviously, I haven't forced myself to commit to just ONE CCW option, but after packing a Glock 19 for a few years then switching to a Kel-Tec P-3AT (since replaced by the Ruger LCP), it's like night and day for convenience and comfort.

If I wore a vest/jacket/un-tucked shirt every day, my first choice would be a Ruger SP-101 .357mag, but that's not the world I live in, so I picked ONE that would suit EVERY attire (Ruger LCP). On days I have a chance to wear "winter clothes", I occasionally carry a bigger piece, but more often, I just carry the LCP out of habit.

Nobody is going to argue with a 380acp at 5-10ft, and you're hard pressed to justify that your life is in danger if an attacker is 20yrds away, so power factor for me is moot. I also DO have a few coyote skins taken with a Walther PPK/S that would argue that the .380acp isn't underpowered at 25-50yrds.