I prefer revolvers for concealed carry in the main. If I thought I was going into combat, my choice would be different due to the differences between self-defense and combat, and I probably wouldn't be too concerned about concealability. Since personal self-defense generally doesn't involve laying down a base of fire or suppression, I don't need what some commentators refer to as "firepower." What I need is something that works every time, is concealable and has sufficient power to stop an attacker. What I want is something that works just like every other gun I might carry. My solution is revolvers.
The big questions are, "What kinds of revolvers? What caliber revolvers? What barrel length/frame size revolvers?"
As much as I love single-action revolvers, concealing one tends to be a problem especially since most of mine are .45 Colts. So, that leaves double-action revolvers. While I really like Colt Detective Specials, they have moved into the realm of collectibles. That leaves any number of other makes. Since Smith & Wesson and Taurus use the same basic system of cylinder release (push forward on the latch), that's what I elected.
Caliber is a subject where everyone has an opinion. My primary defensive caliber is .357 Magnum with 125 grain jacketed hollow point (JHP) bullets. My reasoning is that not only do the Evan Marshall and Ed Sanow statistics from Handgun Stopping Power: The Definitive Study show that round to be right at the top and whenever a new defensive pistol round is introduced the developer compares it to the .357 Magnum, but this powerhouse is available in readily concealable handguns. My secondary defensive caliber is .38 Special +P with a 125 grain JHP bullets. It isn't the powerhouse that the .357 Magnum is, but it is adequate and can be used in .357 Magnum revolvers. It is also more controllable for someone who isn't a dedicated pistolero.
While there are those people who can conceal N-frame Smith & Wesson or Colt New Service revolvers, I'm not one of them. The choice for me is a K-frame Smith & Wesson or smaller. In particular the Model 13/65. My preferred barrel length is three inches. I can conceal a three inch Model 13 easily, and it doesn't get in my way performing normal movements like sitting in my truck or riding my scooter.
So we come to my concealed carry battery: (1) a .357 Magnum S&W Model 13 with a three inch barrel and Bianchi Lightning grips, (2) a .38 Special Taurus Model 85SSUL* with a two inch barrel, and (3) a .32 ACP Kel-Tec P32 (Okay, it's an automatic.). When away from the house I carry the M13 IWB on my right side, the 85SSUL IWB on my left side, and the P32 in my pocket. At home, carry the M85SSUL strong side and the P32 in my pocket. If going somewhere where the revolvers would be too intrusive (a rare occasion), the P32 goes it alone. The biggest change comes during the winter when my four inch S&W M681 replaces the M13 on my right side in a Bianchi #7. That moves the M13 to the left, and the M85SSUL moves to a coat pocket.
You may have different requirements and different solutions, but that's what freedom is all about.
*(Stainless Steel Ultra-Lite)