We were at the Beef Island airport on Tortola with a large cart with all our duffel bags (8 people in our party) when we bumped into another guy waiting for a taxi. He had just one small bag and so I struck up a conversation with him. He was on his 22nd sailing trip and said he brought less and less each time. He brought just two tshirts and a swimsuit and was wearing a button up shirt, pants and sandals. While I find this extreme, it’s good to limit yourself with what you bring.
For clothing, I don’t like cotton clothes very much. I have opted for a lot of quick dry clothing which comes from companies like Columbia and REI. The tsunami and bonehead shirt lines from Columbia are fantastic and their pants with zip off legs are great too. Both my wife and I bought short and long sleeve shirts and pants with zip off legs. I will bring one tshirt, two swim suits, undergarments, hat and sunglasses in addition to these clothes for 16 days in the Caribbean.
One more thing to consider about going into town — from what I have read, it is not acceptable to wear swimsuits.