It depends on how much you can afford. Personally I like heavy pistols very much but those cost a lot of money where I live so I stick to cheaper options like Glocks, XDm's etc. Those are proven over time and can't go wrong with them. Regarding the safety issue with Glocks, you have to know when you have a bullet in your chamber, as with every gun. All the rest is dry firing. Glock 19 sounds like what you're looking for.

Everyone has their favorite gun brands. I like several, so I wont point you at a brand. Here's the most important thing in my opinion: pick each one you are interested in up and hold it like you are going to shoot. If you're a "one gun guy" (at least for now), the gun you choose should be very comfortable in your hand and you should be able to reach the trigger with your wrist in line with the barrel.

Also, think about a .22 down the road. I wouldn't be a decent shot now without hundreds of thousands of .22s sent downrange.

Visit a major gun show and handle as many handguns as you can. It already sounds like you've taken a decision between a revolver and a pistol so the next step is to try to narrow down your selection candidates. Stick with quality, don't go cheap, because you said you intend to carry this gun as well. If you're going to stake your life on a sidearm, it better go band every time you pull the trigger.

Next up is going to a range where you can rent guns. You want to try as many of your candidate guns as you can to see which ones work best for you. We can give you all sorts of information, good and bad, but in the final analysis, it's really what is best for your specific wants and needs. As for external safeties, that is a personal preference. I don't care for them but that's my opinion. It is what YOU want... not what I or anyone else wants or thinks you need.

You mentioned the Smith and Wesson M&P series and Glocks. I have a number of examples of each and either one would be a fine choice. I carry a gen3 Glock 23 as my primary carry gun, but have three M&P's in my carry stable as well. Both would serve you well. The Glock is easier to clean and has a superb history of reliability. The M&P has some of the best handling ergonomics you will find, but it is sensitive to dirty magazines and I think its loaded chamber indicator is useless (think using it in the dark).

Take your time, don't rush things, and continue to research and refine your selections. And good luck.