Well, we're off the St. Augustine on Saturday. We've been many times and still love it!
If you've never been and will be in northeast Florida, you must go. It is the oldest continually-occupied city in the U.S. It has such a wonderful feeling, especially early on Sunday morning. So quiet and peaceful. I like to sit on the balcony of the St. George Inn and watch the early-morning joggers and walkers moving about.
There are tons of shops, restaurants and bed-and-breakfasts in the old restored town. Bring your walking shoes - tons of walking. Or you can take the trolley on a tour of the city and get one and off anywhere you like. Highly recommend doing this. Especially if your staying a few days.
Need something to do at night? There are several ghost tours - both riding and walking. I've done both and they're both fun; as long as you get a good guide. See all the orbs I caught on film. Spooky!
If you get tired of all that history, you can always go to the beach - about 15 minutes away.