Beware the man who only owns one gun, he probably knows how to use it.
Well, that probably doesn't apply to any of us, or anyone we know; we mostly own several or even many guns.
If I were limited to only one, it would be my Glock 26 because I can almost conceal it in a pocket and I shoot it very well. And I like 9mm, in the right gun.
I'd rather have my Glock 17, but here on the tropical beaches we don't wear cover garments, or holsters or belts, or socks, and open carry is generally illegal.
I often carry just my Kel-Tec P32, and I'm very often the only one who didn't leave his gun at home or in his car.
Anyway, it beats a NAA Mini-revolver, like a brick thru a plate glass window.