How come no one mentioned the moi cage site out past Pinnacles near Ewa beach? There are a few moi cages in the water there and underneath a bunch of sharks (Galapagos and Sandbar) hanging in 140fsw. I don't think the fish growing operation is active any more, so who knows how long they'll be there.
Also, you could always follow the shark snorkeling boats out of the N. Shore and head to the snorkeling site in 300fsw. If you got the guts you could roll over the side of your boat no cage! Galapagos and Sandbar there too, every once and a while a tiger, and a few years back Jimmy Hall got famous while taking a picture with a 20' white shark. Hoo ah!
Hammerheads off Molokai at Elephant rock is cool too. We overnight it over there a few time a year mostly for that dive, but the dives off Kalapapa are good too.