We've done the Eastern twice and have a 3rd one planned for May 17.
On St Maarten, we like to do the Goldne Eagle Catamaran in the morning, retunr to the ship in time for lunch, and then spend the afternoon shopping.
On St Thomas, we head over to St John and Trunk Bay Beach. This next trip, we are planning on renting a car and taking the car ferry to St John and exploring as many different beaches as possible.
I have to agree with goofydadeo, Trunk Bay is our favorite place!