We joined a horse named Valentino, and his driver who gave us a very pleasant 20 minute tour of one corner of Central Park, past the Plaza hotel, the Carousel, the midway and the pond. The driver was very knowledgeable and told us a lot of interesting anecdotes about the history of the park. All in all I'd recommend, but it does cost $54 for 20 minutes, so walking might be a better option if on a budget or wanting to see more of the park.
Driver also let our baby feed the horse a carrot after the ride!