To add to the post above, you will also likely find that one carry gun isn't really optimal, just like owning one screwdriver or one pair of shoes isn't really workable. As much as I love carrying my 4" Model 19, there are times (like when my back is acting up, or if I'm working on the car) that it just isn't practical to carry. That's when a smaller gun comes into play.
Some folks here are blessed with the ability to shoot an ultra compact gun as well as larger platforms, but most of us (myself included) aren't able to do that. So we make compromises. The handgun I shoot best is my 4" S&W Model 28. It makes even me look like an expert shot. For me, missing is almost impossible with that gun. I carry it when I can, but it is a fat pig, so it doesn't get carried everyday. It typically gets carried when I'm going someplace with a higher threat level, and I dress around it. I shoot my smaller Model 19 almost as well, so it gets the nod most days. I also have a S&W Model 66 2.5" and a Model 13 3", both with round butts and compact walnut service stocks, that get carried when I need fairly deep concealment (such as when where a T-shirt). The 1911 gets carried when I need my pockets free of speedloaders for other stuff, as I have a mag carrier for the spare mag.
Then, I have my puny S&W 642, which can be carried about anywhere doing any activity. Though I shoot it relatively well, I'm just not as confident with it as the larger guns described above.
This is just as example for your consideration. The guns you select may well end up being different, but some of the rationale you use to get there may be similar. The end goal is to always have a gun (one that is obviously reliable) whenever it is legal to have one.