Having just just returned from a week on LHI as a first-time visitor, I have several recommendations.
Pinetrees is a great place for families as it's central and so close to the main lagoon beach - great for a quick swim unlike some other places which are up on the hillside. The meals are great and if they're included in the tariff, that's even better as it's dark at night and that makes it tricky getting home on your bike from another restaurant. (Memo: take a torch or even a bike lamp for night cycling). Anyway the food is good enough that most people aren't bothered to go out at night.
Capella is obviously more expensive and more exclusive. Apparently they will not take small children in the future and that will be a good thing if you really want a lovely quiet break. It is also quite a distance from the main part of the island altho this is not necessarily a problem if you enjoy a bike ride and there's often a golf buggy available. The views are to die for, the decor is gorgeous and the food terrific. There are a number of good walking tracks in the vicinity, there's a lovely beach a few minutes away and it's the closest accomodation to the Golf Course. I would love to go back tomorrow- a true away- from-it-all luxury holiday.
Recommended activity: Watch out for Ian Hutton if you are interested in natural history. He is the resident guru and gives a series of fascinating short talks at the museum on island geology, history, plants, birds and marine life. Go to the museum information desk for walking trail maps too.
Memo: Before you go, leave your itinerary and hotel phone numbers with your next of kin/neighbour or significant other as you cannot use your cell phone on the island and most places do not have a phone in the room . We had a family member fall seriously ill at home while we were away and no-one knew how to contact us.