The lost footage from Fritz Lang's Metropolis being found in Argentina is one of those things that completely astounds me. In the early 1980s, a completed version of Carl Dreyer's The Passion Of Joan Of Arc was found in a Norwegian mental hospital, after being thought lost. I don't know how this Metropolis footage holds up, either in terms of print quality or in the story being told, but the Dreyer example (in its restored form, probably my favorite silent film, beating out Murnau's Sunrise) gives me hope.
It all stands as a testament to the resilience of analog recording media.
Even though we'll probably never see the original cut of The Magnificent Ambersons, Orson Welles' vaults still promise riches I hope to see unearthed before I die.