I found The Da Vinci Code to be an absolutely gripping thriller. What I really liked about it was Dan Brown’s ability to weave intricate historical details while maintaining the brisk pace of a murder mystery. He really comes across as an intelligent author with all the cryptexes , puzzles and the intricate plots.
As for the grail, I think he has put forth an idea that very few ( I presume) had even an inkling about. So, it certainly changes the readers views about the faith of christianity. I haven’t got a chance to read people challenging/supporting Dan Brown’s views/claims in the book, but if everything in the book is to be believed, I would be totally convinced.
The news abt the movie to be made after the book came when I was towards the end of the book.. so I subconsciously visualised Tom hanks doing a Robert Langdon. Thats going to be one very eagerly awaited movie.... According to a French friend, there is now a tour in Paris that takes people to various locations that the Harvard symbologist and the French cryptologist visit in the thriller- the Da Vinci tour ( anyone with enough money and time :-))
Overall, a superbly written thriller leaving the reader both entertained and educated....