Migflanker, I like some on your list like
GALAPAGOS
NIAGRA FALLS
I wouldn't mind checking out EASTER ISLAND
TIMBUKTU
TIBET

But you know what too? Where there is such a list of beauty, it suddenly becomes a TOURIST TRAP. Some of those Pacific Islands little mentioned or known about is probably a great bet for visiting. I mentioned NAN MADOL in POHNPEI ISLAND. The Venice of the Pacific. Great water falls. I haven't been but wouldn't mind checking it out. There is YAP, PALAU, CHUUK, KOSRAE. In the South Pacific, around the MARQUESES, TAHITI, SAMOA, TONGA each with hidden secrets, such as cliffs, waterfalls, beaches, mountains, coral reefs, sunshine all year around, uninhabited islands and very little spoiled by tourism. Excellent snorkeling and diving, great fishing. Maybe not a top natural wonder but a place to get away from it all definately.