If you like Scuba and/or snorkeling, this is the place to do it with crystal clear blue water. Rent a convertable and drive the road to Hana, but don't forget to pack a picnic lunch.
Quick Tips: Break up the day a little and spend the morning on the beach and relax, then get changed and do something fun in the afternoon. Of course, one morning you will have to get up early to bicycle down Haleakala.
Best Way To Get Around: Even though Maui is an island, it is a big one and going from one end to the other can take more than an hour. So, renting a car is a must -- and since you are on vacation, splurge and rent a convertable -- the only way to drive!