Just get you one of these
I think the absolute worst advice I hear given to a person that is considering a firearm for personal protection is;
"Get yourself a ___ model ___ in ___ caliber, that is the only thing that is worth carrying." (or words to that effect)
Time and time again I hear or read supposedly well meaning people give that advice. Many times it comes from a friend or family member, often times it is repeated on message boards all over the internet.
Yes there are certain firearms that are not suitable for self defense. The Raven comes easily to mind along with several others. Advising a person what not to get is a whole different ball of wax than telling them specifically they need to get X.
Firearms like people come in many different shapes and sizes. To say that a specific sidearm is right for every one, just because it is right for you or that a famous so-n-so wrote it in a magazine is not good advice and potentialy does far more harm than good.
As most people that will read this are aware, serious firearms for self defense are either revolvers or semi-automatics. There are those that feel a low capacity revolver is obsolete and a person is not suitably armed unless they are carrying a semi-automatic with at least a 15 round magazine. The problem that some people have with the semi-auto variety is the strength it takes to cycle the slide. I have found this to be something that effects both men and women, especially those of smaller frame or an older age. For those that do not intend to become afficionados of pistolcraft or have difficulty with the operation of a Semi-auto the simplicity of a revolver may be the best option.
These are things that cannot be known until some time is spent with competant supervision handling various firearms.
In order for a person to be confident with a firearm it must be something they understand and be comfortable with its size and operation. A Barreta 92 is a reliable and formidable firearm, it is just too big for many people to handle and conceal without difficulty. Conversely a Khar can be a bit small for some people to shoot comfortably. That is not to knock either of these firearms, they are only mentioned as extremes.
Caliber is a consideration, but it should not be the sole determining factor in the selection process.
Caliber is really only important to the extent that a person can handle the felt recoil. Granted, as there are certain firearms that are not acceptable for self defense, there is a caliber threshold that should not be crossed. Generally speaking it is best to stay away from the twenty-twos, twenty-five, and thirty-twos for a serious primary personal protection handgun. The .380 caliber firearms should be the smallest caliber one should consider and truely there are few people that cannot handle the felt recoil of the .380's, the .38 special or 9 milimeter for that matter.
Certainly a 45 or 40 is a better choice than a 9 milimeter, however if a firearm in one of those calibers is too big for the users hand, too hard to conceal or has too much felt recoil the owner won't put in the range time or carry the firearm. This in itsself defeats the whole purpose of the aquisition in the first place.
Practice sessions must be enjoyable and if a firearm is two heavy to carry or hurts too much to shoot there will be any number of excuses for not putting in the time necessary to become proficient.
A sidearm is a personal choice that can only be made by the person that will own it. It doesn't matter a Tinkers darn how you feel about the gun you carry, it may or may not be the right one for me, or anyone else. That it works for you is the important thing.
If someone is intent on "helping" a person, it is far better to offer an array of suggestions. No it is not generally possible to "try out" all of the various options unless a nearby range has the facilities to rent any and all of them, which can also be an expensive proposition. Several trips to the range with friends and or family that own firearms will allow a prospective purchaser the opportunity to handle and fire a few different sidearms in various calibers, anyone of which may be the firearm that is best suited to the new shooter. Once the caliber question is settled in that it has been determined that the recoil of certain calibers is acceptable then a specific firearm can be sought.
If, for example the prospective buyer is comfortable with the recoil of no more than a 9 milimeter and can reliably cycle the action then all that remains is to "shop around" for a make and model that the recipient will feel comfortable carrying and want to practice with.
In the event that a person does not have the friends and family available to make the fore going a reality, the enrollment in a basic firearms safety class is a good and recommended option, especially if there is no or very limited experience with firearms. Many times the instructors of these classes will have various firearms available for use by the students.
Resist the temptation to proclaim the one gun that you have selected for yourself, take some time to introduce the new shooter to alternatives that may be better suited to their strengths and weaknesses. In the long run they will be much better armed and more enjoyably progress on the range with a gun that they will carry instead of leaving at home because it is to hard to operate, too heavy or just hurts too damn much to shoot.