Either Barbados or Nevis would be a great choice. Both have awesome restaurants and some culture. Both are beautiful and have some historical features, as well. Barbados has the beautiful beaches, which you have stated you are not interested in and is larger with more of everything. Nevis is a very rewarding place for it's monkeys, locals, it's hiking and its a unique island.

First off, there's no one "best island" - each one is different and has its own unique charistics. You can find some very good general descriptions of each island by using the "Destinations" link at the top left of this page - click through to the Caribbean and read the summaries for each island on your list. That will help give you a "feel" for what each island has to offer. You should then be able to narrow your choice to one or two islands that most fit what YOU are seeking.

Since you are only going for 3 days, I'd concentrate on those destinations you can reach either non-stop, direct or, at the very most, with one connecting flight from your departure city. You don't want to waste time travelling to/from your vacation island.

Considering your interests I think St. Kitts would be a good choice (with a day trip to Nevis if you feel inclined to squeeze it into your brief visit!) .

You could easily fill 3 days without setting foot on a beach by visiting Brimstone Hill Fort (see link below), A rainforest hike, a trip to Ottley's plantation inn (link below)and a tour around the island.

http://www.brimstonehillfortress.org/

http://www.ottleys.com/

For such a short trip though I'd pick which ever island was the easiest to get to!

I agree with sassy_cat. St. Kitts has some great sights and the fort was very interesting IMO. You can rent a motor bike and travel the island as well.

Thanks for the replies, St Kitts no longer works because of flight schedules and we've ruled out Trinidad due to safety concerns. Now I need to choose between Barbados or St Lucia. Which island is easier to get around using public transport, I get the impression that public transport in St Lucia is unreliable.