I used to live in St Thomas many years ago (my grandfather lived there; I just got to 'visit' for extended periods of time!) and I would recommend avoiding Megan's Bay. It is very, very touristy...too crowded, too commercialized... If you only have one day in St. Thomas, I highly recommend taking a ferry or sailboat to St John's. It is much more quiet, beautiful, and secluded... Just my opinion!