If you like photography then taking photos of people and places in Havana is amazing. If you can learn the Spanish for "may I take your photo" you will be rewarded with some really great shots:
www.alib.co.uk/photos/index_cuba06_people.htm
Stay at least one night in the Hotel National just for the history. The view from the garden is amazing. Grab a drink and watch the sun set over the old city.
For more personal tips see my guide with a couple of suggestions:
www.alib.co.uk/guides/index.htm
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