When you're in Oahu I highly recommend the
Turtle Bay Resort (
http://www.turtlebayresort.com/). It's in Northern Oahu and about right between the famous North Shore and Polynesian Cultural Center (10 or 20 minutes drive to either location in opposite directions)
The place gives you the Old Hawaii feelings because of its beautiful yet somewhat seclusive location. It also has very excellent tennis and golf facility there too.
Many national and international events have been held there.
Many Hollywood movies have also been made there. The most recent one is this
"Forgetting Sarah Marshall" movie (
http://www.youtube.com/watch?v=D9podUETps8).