In pistol ammo? The consensus of opinion on this board seems to favor Federal, 'HST' or, Winchester, 'Ranger T'. Other good choices, all of which I happen to use, are Remington Bonded, 'Golden Saber'; Speer, 'Gold Dot'; and either Winchester or Federal, 'Premium' self-defense ammunition.
Over the past several months I've, also, started to use Fiocchi, 'Extrema' self-defense ammo fitted with Hornady, 'XTP' bullet heads. It's very decent ammunition that doesn't have to take a backseat to any of the more expensive, 'big name' pistol ammo. Truthfully, I wouldn't want to get hit by any of the above!