Going to Florida ... what do you advise?

[AFApresident]

St Augustine is nice too. It is the oldest spannish settling on the US mainland, nice little town.
Also visit some of the gardens and plantations you will find between Florida and New Orleans. I recommend Bellingrath gardens (near Mobile, Alabama), but there are many others too.
You can probably also visit the Pensacola Naval Aviation Museum. It´s on your way from Florida to New Orleans as well.

Certainly many things to be seen in the southern US + Florida, be sure to go to your local bookstore or library to read some of the travel guides.