I don't have pictures to post at the moment, but my favorite handgun sight is an aperture rear and a smaller-aperture front. I have that setup on an AMT clone of the Ruger Mark-II pistol.
The rear is a Williams aperture, 'ghost-ringed' by removing the aperture, and the front is the normal wide 'Patridge' blade that I realized was too short for the Williams, by about 0.2"...

So I used a round file to make a groove in the front blade, then smoothed a roll-pin a bit that was the same diameter as the front sight blade, drilled out the hole in the center of the roll-pin to make it slightly larger and smoother, cut the pin to length to match the blade, and soldered it in place.
If I have time and the light is good, anything inside that front hole, once centered in the rear aperture like a normal 'peep sight', WILL get hit by the bullet, out to 50 yards. If the light is poor or I need to shoot fast, you really can use it as a post, without intentionally aiming low, and you will STILL hit pretty well.
It is my favorite
handgun setup, and I have rear apertures on several other guns with either gold-bead fronts or patridge blade fronts.
I do have one red-dot (Millet 1" tube) on a 22 LR Ruger that I shoot suppressed, and some scoped Contender barrels, but otherwise handguns are all 'irons' of some sort.
I tend to use 'irons' (usually aperture Williams and gold bead fronts) on
carbines except some of the semiautos I have red-dot or holographic sights on if appropriate.
For
rifles, most are scoped, because if I'm going to put up with the extra length and weight of a rifle, I am likely wanting to 'reach out' farther, and will need the magnification.
As far as
shotguns, I don't shoot them often enough to have a preference beyond whatever bead or setup is on the gun from the factory. Usually 'open notch' and 'bead' sights if it may shoot slugs or be for home defense, or just a plain round-bead if it is set up for hunting birds/clay.