I sailed throughout the Caribbean ten years ago and have vivid memories of St Lucia! It probably depends on where you stay as far as where you'll be eating. Up near Rodney Bay (at the marina) is/was the best pizza I've ever had. I also had the most memorable Christmas dinner of my life at Memories of Hong Kong (sailed in on Xmas Day - rough storm). There's an East Indian restaurant called Razmataz that was a frequent stop which had great food! Also in the area is Charthouse which is great for chain food. Further south toward the Pitons is Dasheen which hb recommended and I would definitely go for. Amazing sunset views! Near there are some sulfur springs and a volcano if you're into that. Then further south is Marigot Bay which is a great place to hang out for the day and sit at Doolittle's to have cocktails. Man that was a fun place! That's also a good area if you're into diving. Again up north around Gros Islet are some great local spots. On Friday nights everyone would get together for a "jump up" where there's ALL kinds of people and a lot of music.
If you're into nature, hiking and ocean activities then this is the place ofr you. Back then I was a bartender that would just raise the sails and take off until the money ran out. So I didn't go to the super expensive restaurants and luxury resorts. Of all of the islands that I've been to, I felt the safest in St Lucia and enjoyed talking to and getting to know the local West Indians. I hitch hiked alot and relied mostly on the bus system (a cultural treat!). Enjoy yourself and I guarantee that you will have the best bananas you've ever had!