Depends on the gun and how it shoots them. I use Speer Gold Dot 147-grainers in some guns and Federal Classic 115-gr JHPs in others. I chrono the rounds out of the specific guns in question and then make a determination of what to carry based on how the rounds perform (accuracy, velocity, reliability) in that gun.
I tend to carry the heavy standard-pressure bullets (which I tend to think of as stubby .38 Spl +Ps for semiautos

) in shorter-barreled guns (like my 3" RAMI - I use these heavy bullets in back-up mags supporting the +P 124-grainers I ordinarily carry) and the 115-grainers in more delicate 4"-barreled guns (like my a Luger or my Star BM, tho I think the Star's barrel might be a titch shorter than 4" actually).
I've never found a gun that did not shoot the Federal Classic 115-gr JHP (the "9BP") loading reliably and accurately. My Star shoots them at a decent velocity (barely under 1200 fps), as well. This round is old tech (from the '80s), but decent old tech that gained a fair amount of respect "back in the day."
The modern 147-grain bullets (such as the Winchester SXTs or the Speer Gold Dots) should expand decently at the modest velocities these rounds generate - I recall that was not always said to be the case.
Anyway, either of these standard-pressure loadings would be fine for defensive purposes. If I were going to pick one standard-pressure loading to just recommend across the board, though, it would be the Federal 9BP 115-gr JHP. Accurate, reliable, decent and not too hard to find (Google is your friend).

Good luck with your shooting.