I whole-heartedly believe in Atlantis. My sophomore year of college I studied Classical Greek and Roman myth. One of the books we had to read was Edward Tripp's Classical Mythology, it is a type of encyclopedia, and it mentions Atlantis. We looked into the possibility of such a city that could have existed and what it would have been like, when it would have existed, how advanced the people would have been. There were a great number of inconcistencies found, but I still believe that it did exist and I hope someone finds it someday. I believe that every myth is based on some sort of fact and this myth is far to popular to be solely legend.
I especially loved Sherrilyn Kenyon's portrayal of the city of Atlantis in Acheron of her Dark-Hunter Series. She gave a beautifully realistic description of the city, though it wasn't so in the eyes of the main character. Her entire series plays on Greek myth, though not always entirely accurate, but it does explain how the Greeks and Atlantiens would have been related and how the Pantheons would have been towards one another.