Do you mean treasured by myself, or treasured by the person who lost it? Do you mean "Most Valuable"? (Because I don't think I can answer that one in a public forum...)
i would say a 1733 KING GEORGE found at the former headquarters of a general in the revolutionary war. i wont name the general since the folks that own the property dont want a ton of people showing up at thier house to detect, but it was my favorite find. i think its safe to say that this coin was handled by the general or at least by someone who knew him.