Little Havana in Miami. Shop around and find a good hotel rate after the winter rush and have a great time. I have been several times and will take the trip many more I hope. There was a Thread a while back where several of us posted a lot of info on things to do there.
I was not clear on this but as mentioned by another you don't want to get a hotel in the Little Havana area. Stay downtown or at the beach. I have gotten Enterprise Rental Cars there online very cheap but usually off site and not at the airport facility.