I'm with BB. There is no best pistol, just as there is no best car. All of them have advantages and disadvantages. The best compromise of features for me might not be the best compromise of features for you. I recommend that you look at 9mm and above.
The most important things are that the pistol is 1) reliable and 2) fits your hand. People with small hands often have trouble with double-stack designs. People with weak hands/arms often have trouble racking the slides of some semi-autos (particularly the compact ones).
What you prefer really winds up to be personal taste.
First, decide what type of action you want: single action (SA), double-action (DA/SA), double-action-only (DAO, or striker-fired (e.g., Glock). Each has advantages and disadvantages. I prefer a gun that has a consistent trigger pull, that is an SA, DAO, or striker-fired. In contrast, a DA/SA gun has two different trigger pulls that you have to learn: a long, hard double-action first shot, and short, easy follow up shots. You can learn the transition, but I believe it takes more training than learning how to operate the safety on an M1911. YMMV.
Some folks don't like single-action M1911s and some folks swear by them. You can get a very nice, short, crisp trigger pull on an M1911. But you also must learn how to operate the safety.
The Glock and Kahr are striker fired, have a consistent trigger pull, and no manual safety. The stock Glock trigger is about 5-6 lbs with a short trigger pull, but it is kind of mushy with a "sproing" when the striker finally releases. I find the Glock trigger hard to master, but it can be done. I've seen some folks shoot very accurately and quickly with Glocks; it's just not my favorite. You can also change the trigger very easily on the Glock, with options of 3.5, 5-6, 8.5, and 10+ lbs. Glocks are very reliable.
In contrast, the Kahr has a longer, smoother trigger pull. I prefer the Kahr trigger, but the longer pull does slow down followup shots. My three Kahrs have been very reliable as well.
Some DAO guns have very nice trigger pulls (e.g., S&W 3953), others are pretty nasty. Some folks like having a manual safety. Some folks won't carry a gun with a manual safety. Your choice.
For concealed carry, I find that thin, single stack designs are easier to conceal. However, the single stack design also gives up ammunition capacity. Personally, I carry a Kahr MK9 (6+1 9mm) most often. But there are a lot of folks who would prefer a 10+1 Glock 26. The Glock 26 is wider, however.
There are a lot of good guns to consider, including Sig, HK, Beretta, Glock, Kahr, S&W. Some particular models to consider would be the Sig P239, HK USP Compact, Glock compact and subcompacts (19/23/etc., 26/27/etc.), Kahr K9/P9/MK9, S&W single stack (3913/3953/4053/etc.).
Shorter barrels are more comfortable for me to carry, especially when carrying IWB. But the shorter barrels typically result in a heavier recoil spring, making it harder to rack the slide. More importantly, the shorter barrels give you a shorter sight radius, making them harder to shoot accurately. Examples are the Kahr MK9, vs. the Kahr K9, or the Glock 26 vs. the Glock 19. You'll have to decide whether the tradeoff of easier concealability versus less shootability is worth it to you.
M1911