Going to O'ahu, (if you never get out of Honolulu/Waikiki) is like going to San Francicsco, only a bit more tropical. NASTY traffic, LOTS of tourists, LOTS of crime. Granted, once you get out of the city, the island is beautiful, and there's a lot of things to do, but you HAVE to rent a car. Public transportation for tourists just sux. MOST hotels charge $25/day (or more) to park your rental car...that jacks up that cost. We go to Maui at least once per year average. (We own a timeshare in Ka'anapalai) and like it much more than O'ahu. You have to rent a car there. NO viable options. Big Island is nice. West (Kona) side is deserty, with lots of baren lavascaped areas, but the east side is (for the most part) lush and green. Much more "rustic" and less developed than O'ahu or Maui, and things are spread out. Biggest island of all, and bigger than ALL the others combined. DEFINITELY have to rent a car. Kauai is nice and green almost everywhere, and much more laid back than the others. Once again, you need a rental car to get around.