124 gr Gold Dot is great. I don't use the +p version. Just the regular version. Pay attention to that when you buy it if you go with that. The box looks the same except for the "+p" on the label behind the "124gr"

I also like 124 gr Hydrashok from Federal. Its a little older technology, but I still like them. I have carried them so long that I have fired tons thru my carry gun.

Besides reliability, you need to pay attention to POI/POA. Not every hollow point round I have tried hits where I aim. The hydrashok is like a laser gun from my Berettas.

I only switched to Gold Dot around the time Obama was elected because the 124gr Hydrashok round supply dried up EVERYWHERE for about a year. So, 2 of my guns run with Gold DOts now. The rest are hydrashok (I can find them again now)

My personal choices are the Federal HST in 124 or 147 gr. and the Winchester Ranger 124 or 127 gr. Be advised the Ranger 127 gr. is +P+ and my not be suitable for some fireams.

I've had good luck with Speer Gold Dot JHP in my XD40 3". Reliable, clean burning, tight groups.
Can be pricey though.

Sounds like good advisorys and suggestions from posts # 2, 3 & 4 - don't think any of them can be dismissed as anything but seasoned experience talking.
I can't really add any new information at this point, while I'll venture to say that Herr Luger did, as most firearms folks know, design the 9mm for 124 gr as Shipwreck specifies.

Hud is also on the same page of good advise - imho - with including the 9mm 147 gr in his favored choices - a recommendation that a lot of sure shooters may not agree with, but, it works for me; esp. the Federal HST jhp 147 gr., with 'plus P' as optional. Gotta go with the flow on offerings of Gold Dot and Ranger T also.

Speer bullets - projectiles per se - and Barnes, along with CCI primers and Nickel plated 'brass' (casings) will probly and consistently serve you well in all popular calibers.