We just returned from Maui and Oahu on Monday and had a great time. If you're in Oahu, Pearl Harbor Memorial is a must see. We wanted to go gliding on the North side in Haleiwa but didn't have time

In Maui, we drove the road to Hana and continued all the way around Haleakala. This is an all day trip. Another day we drove to the top of Haleakala (1/2 day trip). The Kaanapli has a great beach and snorkeling at Black Rock. One of the better late afternoon deals is at the Hula Grill happy hour from 3-5pm (at Whalers). We also took a whale watching trip on the Hula Girl www.sailingmaui.com which was fantastic. You leave right from the beach. It also has an excellent kitchen on board and reasonable prices.

There is a grocery store just up the road where the Lower road starts that has everything and decent prices too. About a 1/2mile up the lower road is a place called Uno Kau Kau (IIRC) for a cheap casual sandwich or chinese for lunch.

Have a great time!