I was just in St Croix 12/21/01-12/24/01, although it was not one of my ports. I was on Celebrity Galaxy 12/14-12/21 (out of San Juan), and after the cruise went to St Croix for three nights.
My personal favorite: Buck Island. If you want a more personalized tour out there, don't book a shore excursion - do it on your own. We saw some "catamarans" (that got out there with outboard motors) holding at least 50 people.
Here's my suggestion:
Take a cab from the port (Fredricksted) to Christiansted (I believe it is just under 20 miles).
In advance, book your own Buck Island tour.
We used Captain Francis of www.buckisland-diva.com
He uses his sailboat (and SAILS, not motors) to take no more than 6 (not 60) passengers to Buck Island. You can charter for the day, and he customizes to what the group on board wants. More snorkeling time? More beach time? Another place to snorkel in on the other side of the island? He also acted as a snorkel guide, taking us places off the underwater trail so he could point things out to us. (Can't see a guide taking 50+ people!!)
We booked several months in advance since we knew we would be there around Christmas.
His rates were:
9A-2P $60 per person
2P-6P $50 per person
If you have a cruise that the times don't work for you, you can charter for the day. He sails out of Green Cay just east of Christiansted about 5 miles.
St Croix was well worth it. Other thoughts I have about St Croix: The shops in Christiansted don't open up until 9 or 10 and close by 5ish. St Croix is a community, not a 24 hour WalMart like I have down the street.
St Croix gave us the relaxation we were desiring on our extended vacation. We spent time snorkeling at Buck Island, looking through the unique shops in Christiansted, touring the fort, enjoying meals overlooking the harbor, observing a lighted Christmas boat parade, napping on the beach, and a lot of good ol' hometown hospitality of the residents there.
I'm 27 and was happy there. It had a wide variety of things to do no matter what mood you are in - restful mood, party mood, beach mood, fine dining mood, etc.
One of the neatest things to me was walking into a jewelry shop in Christiansted and purchasing jewelry... directly from the person who designed it! Bought a nice "Hurricane George" bracelet from one little shop and some elegant earrings from another little shop (and the only girl working in there was the designer!). Didn't go in Colombian Emeralds or Diamonds International since those were at all of our other ports and were promoted hourly on the ship. Did not go to Fredricksted. Hope this helps by giving one person's opinion of St Croix.
Of our 7 night cruise (Southern) plus the three nights in St Croix - this was our favorite beach (Buck Island).
-Mandy in Dallas