Our family has been to Maui a few times and also Kauai, and my wife and I went to Oahu for a professional conference for me a couple years ago.
On this trip, we are taking our son and a friend of his to Oahu for 3.5 days so I can take the boys to Pearl Harbor and check out the island a bit. We are then going over to the big island for another 3.5 days (they have never been, I haven't been there in about 35 years). So that island should be a pretty new experience for all of us.