If you are into tours take the Kualoa Ranch Tour. For th Half Day tour I took the Movie Sites & Ranch Tour. Lost had just filmed in the bunker three weeks before my visit and will air in February. Movie sites such as Jurassic Park, Godzilla, 50 First Dates, Lost and Mighty Joe Young have filmed on the ranch. The narrated excursion into famous Ka'a'awa Valley is a beautiful way to spend some time on the island.
Click on thumbnail to enter gallery and enlarge images.
I also enjoyed the Horseback Tour. The guides and trail were very easy. The views are simply amazing.