Well, one of my favorite places I ate was Ruth's Chris Steakhouse in Lahaina. Great food, but big bucks. They had great sushi at Sansei in the Kapalua Bay Hotel. Have lunch at the Hard Rock Cafe in Lahaina just because it has a great location and atmosphere.
My favorite place was the Seven Sacred Pools past Hana. Great bit of cliff diving!
The small beach at Kapalua is very nice. Good for scuba diving and lounging, but not for surfing. Lahania is nice for surfing. Just east of Kapalua there was a great cove for snorkeling.