A shopaholics' paradise! Take the trolly to El Morro and walk down-hill - get a map from the tourist kiosk in Old San Juan - the ones from the ship are useless.
Get a golf cart/taxi from the ship to the dock and then take the ferry to the mainland - there is a beach which is very nice and you can get umbrellas & chairs (we got 2 of each for $20 for about 3 hours) - nice service - GREAT DEALS ON LIQUOR! A liter of Bombay Blue Sapphire for $13, Absolut 1.4 liter 2/$19.99.
Too hard to get to town or St. John's best beach from the ship (cab/ferry/cab + waiting...return + cab/ferry/cab) Fair shopping - Diamonds International had a clearance center on the 2nd floor - we made purchases from the Royal Caribbean Jewelry Store - had just what we wanted with reasonable prices - good service too (got free cleaning, extra links for a watch and free gift wrapping).