I wish I could have spent more time on St. John's, but since my friends live on St. Thomas, that's where I end up staying. We did a day trip over there one day the first time I was there and it was so beautiful. My friends got married at Hawksnest Beach on St. John.
(and of course I can't post about the USVI without plugging my friends' dive op
Admiralty Dive Center These guys have done so much for me over the years and are two of the best friends I've ever had, so I plug them every chance I get. If you are looking into diving around there, call them, ask for Laura and tell her DollFin sent you her way - she'll give you tons of great info on their dive op as well as the islands in general.