I lived in Hawaii for a while and there are some really great things that I figured I could probably share with others that may have never been there.  I worked at a restaurant called Leilani's on the Beach in Kaanapali Village.  Great food and decent prices in the downstairs beachside grill.  If you want some great taco's at a great price, check out maui tacos.  I know it's a chain, but it is sooo good.  Definately rent a car and drive over to Hana if you really want the Hawaiin experience.  It is a beautiful rainforest and a great place to camp.  You can set up your tent, have a bbq, and take a swim in the seven sacred pools all for free!