There are two primary schools of thought when it comes to choosing a handgun to conceal. The first could be called the change your clothes to fit the gun you should be carrying. They claim and with a certain degree of accuracy that simply by changing your wardrobe you can easily conceal a full sized handgun. You see them wearing a coat when it is unseasonable, white t shirts and tank tops with an open bowling/ Hawaiian shirts and 5.11/ photographers vests. Seriously, unless you have all kinds of cameras and photographic equipment hanging from you or you are actually on a safari that vest isn't fooling anyone. If you are just meeting the legal requirement to cover up your gun that is cool but if you think everyone doesn't know you are packing then you are sadly mistaken. For the sake of convenience we will call them vest people from here on.
The second group says you should select a gun that fits with your current wardrobe and will be easy and convenient to conceal. They like slim sleek little guns. Guns that are smaller than a deck of cards and have cute little bullets. They like to hide these slim sleek little guns in all sorts of creative areas like ankles, pockets and their underwear. I wish I was joking about the last part but it is true. For the sake of convenience we will call them pimp gun people.
So who has it right? I would say both of them have part of the truth. Vest people can point out many cases where a very small gun which holds few, relatively weak cartridges is simply not adequate. They maintain that it is best to carry a full sized handgun, 2 spare magazines and sometimes all sorts of other stuff.
I think when it comes to concealed carry vest people fail to consider that humans are involved. We are, at least to varying degrees lazy, not prone to change and creatures of comfort. If something takes a lot of effort, forces us to alter our lifestyle or is uncomfortable we will not do it. I have found that concealed carry doesn't escape these unavoidable truths. There is a saying I heard once that 'if anyone every says they concealed carry a 1911 I ask them to show it to me, right now' and almost invariably they mumble some excuse for why it is in the truck or the nightstand. While some folks do in fact regularly conceal full sized handguns I think if they are pragmatic about it they would agree that they are probably in the minority.
Most people simply will not conceal a full sized handgun with the regularity required to reasonably assume they will have it when they need it. You might be the exception but far more times than not the big, heavy full sized pistols get left in cars or nightstands. While those are both fine places to have a gun the point of having it when you are say, walking to your car or in a store is missed.
I will give the pimp gun people credit for being realistic. They probably represent, in the real American gun world away from tactical magazines and fancy shooting competitions, the largest group of people who regularly carry firearms for self defense. However particularly in today's increasingly dangerous and violent world a .22 with a 1.5 inch barrel and sad excuses for sights is probably not the best tool for the job. I also think that the pimp gun people are a bit behind the times. Over the last 20 years, particularly the last 10 or so there have been all kinds of great additions to the gun market. Not so long ago you could have full sized handguns, the ubiquitous .38 snubby and tiny little pimp guns. Nowadays the compact market of handguns offers an array of pistols in normal calibers like 9mm, .40 and .45 that have real sights, hold 10+ rounds and are realistically small and light enough to conceal given modest allowances. Glock, Sig, HK and all the big players have a slightly scaled down version of their full sized model which fits this bill nicely. Personally I really like the Glock 19.
Taking a step towards the vest people you might not be able to wear skin tight clothes or walk around in swimwear. However simply wearing pants or shorts with a belt that will support an inside the waistband holster and a shirt/ sweater which is a half size too big around the waistline is a sacrifice which most folks can realistically make. That will certainly allow you to carry a compact sized handgun.
However much I think you should make the above choice do remember to be realistic. A gun you WILL carry is better than the gun you SHOULD (at least according to the gun rag people) carry.