Havana - the Museum of the Revolution, the market in the week and the atmosphere. All the old 50s cars and the back street music cafes.
Trinidad - Plaza de la Musica - excellent outdoor music venue with dance floor and fabulous musicians.
Quick Tips:
Be firm with people hassling you, and they will usually give up after one time of saying 'No'.
Best Way To Get Around:
On a tour or hire a car. Trains are scarce, and it can take up to 3 months to get a ticket. Planes are not recommended, as they are not very safe.