The National Park Service has announced the 2007 National Historic Landmarks Photo Contest. Basically, you can submit a photograph of a National Historic Landmark along with the entry form available on their website. There will be a national winner and six regional winners.
A searchable database of all the National Historic Landmarks is available online -- if you choose Florida from the drop down menu, you'll see that there are nearly 40 sites to choose from in this state alone. (The results will include a link to an address and brief description of each) That list includes big fancy buildings, modest houses, a train car, a schooner, a battlefield, indian mounds, and a wildlife refuge. Something for everyone!
These landmarks struck me as being particularly photogenic, but this isn't a complete list.
Mary McLeod Bethune House, Daytona Beach
Bok Tower, Lake Wales
Cathedral of St. Augustine
El Centro Espanol de Tampa
Fort San Carlos de Barrancas, Pensacola
Fort Zachary Taylor, Key West
Ernest Hemingway House, Key West
Hotel Ponce de Leon, St. Augustine
Marjorie Kinnan Rawlings House, Cross Creek
Miami Biltmore Hotel