Recommended sights in Nassau?

I am making a return trip to the Bahamas this summer and will be going to
Nassau by way of a cruise again. I went last year but an approaching storm
caused us to leave port early. I had time for one shore excursion which was
to swim with stingrays and that was about it. I am going ahead of hurricane
season this time and will have a full day to play ashore. I'm not into
shopping other than perhaps the Straw Market but am more interested in
sightseeing. I have bought some books on Nassau but would appreciate some
suggestions from people who have visited Nassau on what would be good sights
to take in while exploring the island. I have been told that the Atlantis
Casino is something I should see but I would like some additional
suggestions. Thanks.