Totally agree on the Tom Hanks issue. Langdon is clearly supposed to be that intellectual/professor sexy. He always gets a girl in Dan Brown's books!
I went to Saint Sulpice when I was in Paris a few weeks ago to see the rose line and the obelisk. We also wished we had reread the Louvre part before we went because we stared at one of the paintings that was supposed to be "coded" by DaVinci, but we coudlnt' remember what to look for!
