Have been to STX many times and own land there. I have sailed there from the South Shore of STJ twice and it is as described by others. We had fantastic and lively crossings both times with inky blue water (it is really really deep out there) and flying fish, but imagine in bad weather it would not be fun at all. We always watch the weather and get an early start to arrive into C-sted with good light to enter. Agree with Kimber that Protestant CAy is very crowded. We have anchored off of St. Croix Marine on the east side and it can be rolly but the holding was good. There used to be some moorings there but they were gone the last time there. St. Croix Marine has ice and other supplies. Teague Bay where the YC is has good holding. I would call them to see where they would like you to anchor as there are some boats on the bottom in there. Also care needs to be taken to get in there (all well marked and quite obvious but need to do your homework). If you wanted to rent a car for the day or so, I believe that Centerline or Olympic (both local) may meet you at a location. We have friends that live there so have not had to do this.
As for a land based trip we have always rented houses and have used VRBO for the most part. We like to stay on the east end as it is very quiet but only about a 15 min drive into C-stead. There are a few good places to eat on the east end as well--Duggans (can be visited by boat in Teague Bay) and Blue Water Terrace, Shoreline at Chenay Bay come to mind. There are plenty of beaches and you also can hike to some for total solitude (Jack and Issac Bay on the east end). Have also stayed at Chenay Bay. It is a great value and you are right there on the beach with a good restaurant/bar and paddle board rentals etc. The ocean front cottages are more updated (think they are timeshares). On holidays it can draw a crowd but you can always walk down a bit to get away and always have been able to find a chair etc. Have stayed in the villa Island Time (Teague Bay that has two master suites) and villa Panorama (larger house 4BR and 3 BA) and they are both quite nice.
If you like to dive you may want to stay in the Cane Bay Area and it is lovely. Love the beach there and it is less arid with large bluffs above the ocean. There are hikes to the tide pools, you are closer to the rainforest (Domino Club with beer drinking pigs). The west end is all beach (usually calm with little wind) and the town here is F-sted. It is quite sleepy unless a cruise ship is in. Snorkeled the cruise ship pier the last time I was there and it was awesome. Of course you cannot do this when a ship is in. There is also a bio-luminescent bay on STX in the Salt River area (mid-island where Columbus landed) and this is an interesting and beautiful experience if conditions are right. Agree that Cruzan Rum is worth a visit.
Also if you are land based recommend Lewellyn Charters to go out to Buck Island. He runs out of Teague Bay (he may have a website but likely need to call him to make a reservation). He only sails with no motor on his trimaran and he only takes about 6 people so a much more intimate experience. He is also a Calypso singer and was on island when Hugo hit so a great story teller.
Favorite restaurant in town is Savant. Ask to sit in the outside courtyard. There are many good and fine restaurants in town but also casual places for any budget. Love downtown C-stead for the architecture and it is all walkable. Crucian Gold and IB Designs are favorites for local jewelry and Jan Mitchel for fun glass plates. They have an art Thursday where the shops stay open later and serve food and drink which is nice.
STX bad rap I guess comes from the murders (way back in 1980 I think) on a golf course and of course Hugo destroyed the island. I have found the locals to be very friendly and in general the prices and services a far better value than other islands. Are there unsavory parts? Yes. The oil refinery is an eyesore and I don't like chain restaurants but you see the refinery when you fly in and out and don't need to frequent KFC. It is a large island with much diversity.
Hope this helps! <img src="http://www.traveltalkonline.com/forums/images/graemlins/Grin.gif" alt="" />