Probably our least favourite of the ports we visited unfortunately. It would be the dream location for anyone travelling to the caribbean for shopping but that's just not us and as such we found very little to see and do.
An amazing city with plenty to keep us occupied for 3 days! I don't think I really need to say much as it is all in the guide books but we would definitely recommend a 2 hour+ carriage tour of Habana Vieja and then just a 1hr taxi ride to Plaza de la Revolucion - there isn't much to see in Modern Havana but this plaza is a must-see and the taxi drivers at the port are happy to take you out there, wait while you look around, and then drive you back with stops on the way for photos if you see something you like and with the occasional bit of local info thrown in (restaurant suggestions, etc). We would also recommend a visit to Dos Hermanos bar - as you leave the port building, cross the road and turn left, it's about a 2 minute walk on the right. The mojitos are to die for and a bargain at just 4CUP (most tourist bars charge closer to 6CUP) and the bar staff are friendly and chatty - we ended up behind the bar getting our picture taken with the staff!
A beautiful port! Definitely walk along the waterfront (on the shop side if you don'd mind being bothered by shop staff and on the waterside if you fancy some peace!) - the views are gorgeous. For excellent Mexican food and margaritas on the water (including sandy "beach" area and sea access for swimming) head to Jeannie's - once you get out of the shopping centre you want to head away from the main waterfront (if you stand with your back to the ship you're heading right) and it's on the right side of the road just before Jimmy Buffett's.