I just got back from the beautiful Island of Maui after 2 weeks of fun in the sun. Stayed with my wife and twin 7 year old daughters in a small condo located between Kaanapali and Nepili. If you are interested in large crowds, expensive cocktails, lots of people on the beach, expensive meals, then go and stay at one of those huge over priced mega hotels. We stayed at a small 18 unit complex called the Hyochi Nikko.
Our unit included 2 bedrooms and 1 full bathroom, air conditioning which is a major bonus, a remodeled kitchen and a deck that over looked the ocean that was about 100' away. We were able to barbecue every night just a few feet from the waves at our own private beach with unobstructed views of Molokai and Lanai.
After dinner our kids swam in the pool while we enjoyed an awesome sunset sipping a Mai Tai or 2 or 3 or 4. During the day we had a choice of about a dozen local beaches that where no more than a 1/2 hour away, all of which offered great snorkeling. By the way, you can pick up a complete snorkeling set-up for a week for about $13.00 total.
Some of the other things that we enjoyed where swimming in the streams and natural pools in the Aia Valley, Snorkeling in the Olivine pools on the west side of the Island at mile marker 16, enjoying the spray from the of huge blow hole just a few more miles up the road. Also if you need to get away from the family, I would suggest a ride down Haleakala volcano. There are lots of companies that will pick you up at your hotel and take you to the top and you can enjoy the sun rising over the island. Then you can ride down the mountain to the awesome town of Paia and have breakfast at Charlie's. I would order a hubcap. It's pancake that overflows the plate, put some coconut syrup on it.
Another thing to enjoy is repelling down water falls. There is a company that offers this unique opportunity to hike the jungles of Maui and repel down jungle water falls. We also enjoyed the Hana experience, scuba diving off Lanai, submarine ride from Lanai, a couple of Luaus and much, much more. Go to Maui. There is something there for everyone.