For me, I think it would be Aragorn in his coronation outfit. Give him the long flowly cloak, his crown, and a heroic pose with Anduril raised high and there you go.
The model of him at the black gates is cool, even if it does need an update from Finecast, but it doesn't really scream "King Elessar" to me, more "Aragorn, Hero of Gondor"
What would yours be?