There are a lot of good posts here. I'll add an observation or two from my experience.
EVERYTHING depends on how you dress. If you have a jacket or untucked shirt or something covering your belt, you can carry a 1911 in a Milt Sparks Summer Special or some other holster. I have done this for twelve hours a day or more, many times, and it remains one rig that I can go out with and not worry that it might become uncomfortable. With the right holster, and depending on your body shape, there are probably many other guns, including revolvers, that are just as comfortable. Keep in mind that with IWB, you will probably have to have larger pants, although you may get away with your present ones if you stick with a 1911. If your outerwear permits (by concealing properly), you may find a good OWB holster-belt combination more comfortable. However, if you wear fairly close-fitting jeans, you may find that IWB carry actually supports the weight of the gun BETTER than a mediocre OWB holster and belt combo, and probably gives less of a lever arm for the weight of the gun to act over, regardless.
An auto should be used for a while to determine reliability before it is carried. It's nice to practice with a revolver, too, and to know where it shoots, but it doesn't take as long to find out whether it will actually work.
You will probably end up with an aluminum J-frame revolver, particularly if you can't dress properly to conceal a full-sized gun. They can usually be carried in the pocket. Even if you carry a full-sized gun, you should probably have a light J as a backup, as a weak-side gun, or as a gun that can be drawn when seated, especially when belted into a car seat. Depending on how you dress, you may find that it takes three guns rather than two to fill all those requirements if, in fact, you regard them as requirements. Keeping in mind that you will never be able to prepare for all the remotest possibilities, you will have to make up your own mind what is a reasonable price to pay for protection against unlikely (or, perhaps, likely) threats.
Hope that this is of some help. It really just touches the surface.