Consider St. Augustine. As America's oldest city, it has tons of history, art galleries, interesting architecture, many good & reasonably priced restaurants, shopping (2 outlet malls) and nice beaches. The historic district is very walkable.

A few links:
http://www.staugustine.com/visit/
http://www.visitflorida.com/St_Augustine
http://www.getaway4florida.com/
http://www.orlandosentinel.com/trave.../st-augustine/