One of the things that we didn't do last year, but made a priority of this year was the summit of Mt Haleakala to watch the sunrise. Very cold, very windy, and unbelievable. We left the hotel in Ka'anapali 3 hours before sunrise and the timing was just right. By the time the sun came up right at 6am, there was a pretty good size crowd.
We spent a half hour next to a great guy named Rich from New Jersey and he was kind enough to take a photo of us.
If you visit Maui, I really recommend you check this out...and bring winter gear.