I`ve always wanted to dive the Great Barrier Reef as well as some not-so-well-known "special" dive sites like Yonaguni in Japan, but I have another love that will most likely NEVER happen.
I have a friend along the upper West coast who keeps inviting me on one of his runs to Alaska to see the Orca (killer whales). This is something that would be different, but I absolutely would not be able to resist the temptation to dive with them and get some video footage.
Cold water and animal hazards aside, there would be nothing like seeing these creatures of the deep in their world.