Miami is a boring tourist attraction. A few days of fun, and then you're bored out of your mind while looking for something new to do. You can literally hit up all the night life in Miami is 2 or 3 nights. It's longevity is worse than Disney World. The only thing decent about Miami is some of the women, and better can be found in Daytona.
Gainesville, during the school year, is the best place to go in Florida for easy fun and free booze. Daytona would be another place in Florida that you should definitely hit up. Better beaches than Miami, better crowd, and more tits.