Keith, In regards to Amelia Earharts plane being found, Last I heard was that they hadn't found anything conclusive at the supposed crash site to indicate that it was indeed where she crashed.
One of the last naval mysteries of WW 2 is the French submarine Surcouf. Sunk in 1942, officially in an accidental nighttime collision with all hands, her dissapearance has since been surrounded by a cloud of conspiracy theories. The location of her final resting place has been a mystery ever since. Locating the sub (and verifying it's identity with photographs) could put to rest a lot of those conspiracies. For the record, I dismiss those who believe she was a traitor ship, and I believe she lies in the Gulf of Mexico.