The Naked Lady is a sailboat sitting more or less upright in 115 FSW in the Kailua Harbor. It's a square dive to that depth, and by comparison to the wrecks off of Oahu (don't even get me started on Truk...) it's barely qualifies as a "wreck dive". It is somewhat photogenic, and there can be interesting ambush predators lurking about on some of the related debris in the area.
Nearby is the Predator, an LCU sitting upright in 90 FSW. Again not much of a wreck; some days there's all kinds of other interesting stuff there (sharks, male Whitley's Boxfish, the Atlantis Submarine...) but other days it's a small and not terribly interesting hunk of slowly rusting metal.
The airplane wreck is just north of the current Kona airport (KOA), sitting upright in 115 FSW. It's an old Beechcraft, and is only partially intact.
The wreck(s) at Mahukona are pretty well buried at this point. I've found some odd bits of debris, and have heard rumors of some large anchors in the area, but have yet to find them swimming around down there. Better luck with the scooters, and when I get a break from teaching I'll probably be up there looking further afield.
There used to be an organization here (WHARF, West Hawaii Artificial Reef Foundation) with the aim of getting the USS Mauna Kea sunk here as an artificial reef. There was so much local opposition (even from some local dive operators) that the project is essentially dead at this point.