The first thing you need to decide is what type of action you want, i.e. single action only (Colt government model and clones), a gunthat shoots the first round double action and the following rounds single action, or a double action only. If you're going with SA, then you're either carrying with no ammo in the chamber or one in the chamber and the hammer down, neither of which is an optimum state of readiness, or you're carrying 'cocked and locked.' Personally, I am not comfortable carrying cocked and locked, at least not concealed. Too much to go wrong. But that's your choice.

If you don't like those choices, then go with a DA/SA or DAO. 'Concealability' is factor of how you choose to carry the gun, but don't dismiss the larger guns. I only weigh 165 or so and I can put a full sized auto in the small of my back, and you generally won't see it even if I'm wearing a t-shirt.

That first decision will narrow it down for you. I do NOT recommend carrying a concealed pistol cocked and locked. As a duty pistol, yes, concealed, no.