We just went to Maui in January and discovered its a perfect setting to reset and relax. It was our pre-honeymoon LOL. We had a quiet time but two activities we did and I would highly recommend is the snorkelling. This company is more expensive but they don't take out as many people - we only had 12 on our trip I think the max is 30. I personally wouldn't pay the extra for the snuba and definitely pay for the wet suit.
http://www.mauisnorkelsnuba.com/
We also went out on the America's Cup yacht to watch Humpback whales - if you enjoy extreme sailing this might be an adventure for you
http://www.sailingonmaui.com/
This is also a great website with fabulous reviews it really helped me plan our trip
http://www.tripadvisor.com/Tourism-g...Vacations.html
Do you know where you are staying? We have always stayed in Kehei - and quite like it.
Bottom line - HAVE A GREAT TIME!!!