The volcanos are cool on the big island and Waimia Canyon is great too on Kauai. Pearl Harbor is a moving place. My favorite is the Napali coast cruise… But then again scuba diving is beatiful too. Oh I can’t decide. It all great I mean it is Hawaii.
I second gooch… traveling in a zodiac along the Napali coast with spinner-dolphins jumping out of the water next to me is my favorite travel memory, period.
I was just a wee kid when I went but we ended up spending most of our time on Maui island. I went snorkelling with my cousin around a large chunk of volcanic rock that was covered in colourful sea life. We swam around looking at cool fish and plants for hours. I’d love to go back.
From personal experience and having had lived there any place where locals go is the best. If you can find locals to hang with they truly know the best. As a local I suggest the west side of Honolulu.