Florida panhandle

If you visit the National Aviation Museum (highly recommended) and happen to be there at the right time, there are stadium seats behind the museum where you can watch the Blue Angels practice their show if they're in town. And the museum itself is free. If you have kids, there are several things that they will enjoy as well. If I remember correctly, you do have to pay to park, but it isn't expensive.
I was stationed in Pensacola for two years and never visited. I guess it was so close that I could go anytime. I also found that the Enlisted Men's Club served cold beer really cheap. :)