Old San Juan - great city, great food - if you want to do some serious shopping go to Plaza las Americas, it's about 30 minutes from the port - if you like to rum, buy Don Q - you will not find it no where else. They have different flavors.
365 beaches - we went to Church Beach, very nice beach. They have a restaurant at the beach. You must try Rum Punch - make sure you ask them to use English Harbor Rum, very good. I'm don't like much rum, but this rum is very smooth.
My favorite port - love St. Maarten (dutch side) and St. Martin (french side)
St. Maarten - if you are looking to liquor this is the island to buy it - it's cheaper in St. Maarten (dutch side)
Shopping is great.
St. Martin - you can take the public transportation to go to St. Martin - it cost $2 and is reliable. We ate at a bakery (can't remember the name but the name starts with an C) it's located where the flee market is at. They have great pastries.