Buy a few boxes of assorted quality defensive ammo and go with the one your gun likes best.
For me in 9mm, my guns just absolutely love the Winchester 115gr Silvertip. YMMV.
This is something you'll have to determine for yourself, based primarily on what works best in your gun and what you shoot best.
Any society that would give up a little liberty to gain a little security will deserve neither and lose both.
Benjamin Franklin