Scott and Ron,
I'm going to Aruba, Dominica, and St. Thomas aboard MV Sun Princess early next month so I'll post comments when I return.
In St. Thomas, I highly recommend the "Champagne Catamaran Sailaway to St. John" in spite of the $96 price tag. It's worth every cent of that price! The catamaran picks you up right at the pier and takes you to a rather remote beach on St. John. There's also a reef for snorkeling nearby, to which the crew will direct you (and they also provide lessons for those who don't know how). The crew also serves a cold buffet lunch, which is always fresh, while the catamaran is anchored at the beach and they serve beverages (including champagne and rum punch) throughout the whole trip.