I'm imagining a scene in my head that I desperately want to happen.
When, or if, the wall is destroyed and the army of the dead and the Others march down through the Seven Kingdoms, they will need to probably still besiege the castles. When they get all the way down to kings landing, the people there will be well equipped.
First, they will have the large supply of wildfire to burn away any dead attacking the city, but what about the Others?
Well, my theory is that Dragon bone is the missing component needed to make Valyrian steel, and where is there an abundance of Dragon bone? The Red Keep.
They use the skulls of the Targaryen Dragons to forge new Valyrian swords, they will probably need regular iron to help too, so they melt down the Iron Throne itself. And who could smith such weapons?
Well why not a son of Kings landing itself, taught to forge on the street of steel and even has a bit of kings blood to boot. Gendry will fulfill his fathers with to destroy the Targaryen Dragon skulls and forge the weapons that save the day, but no ordinary hammer can shape such weapons. Gendry will have to use his fathers war hammer to smash the steel until it is sharp.
So, some hero will be fighting with a sword made out of Balerion the black dread and the iron throne itself against the others. Awesome.