Stone Armor is still the Gold Standard.
But it pays for that durability with some crippling compromises.
Sure, you won't DIE, but you won't be killing certain enemies by yourself. So everything turns into a pointless slog.
After that, pretty much Inv/ANYTHING. With the current way it runs, and the plethora of choices for Enhancements, this is pretty much the Gold Standard for no-compromises survivability in the modern game.
And, again, due to the choices in IOs, MANY other armor sets stack in QUITE closely behind it.