Naturally, I would begin with Oahu. The capital is there, as most of the population. Beaches are nice there. I was there last January and the guy I used to work with took us around, and he grew up there, said he liked his own island of Oahu the best for beaches. But if you want to see volcanos, Mauna Loa and Mauna Kea are the main ones to see. I saw them both off the coast as my ship went between Maui and the big island Alenuihaha channel. But I can't say I spent time on any of the other islands except for Oahu. If you got the time and you got the dough, see them all.