Puerto Rican coffee is some of the best coffee I have ever experienced. It is like heaven in a cup. When ordering coffee here, do not just order regular coffee. Ask for cafe con leche (coffee with milk). Then add a teaspoon or two of brown sugar (no fake crap). Sometimes you will get lucky and have a fun design in the cream like these cups from a place called Cafetealo in Caguas.
I am quite certain that cafe con leche will be the thing I miss most from Puerto Rico when we leave. Good reason to drink lots of it while we can :)