Well, well, well... the film is finally here. I was one of the first people I knew who bothered to read the original harcover - and truth be told, I did quite enjoy the book for a number of reasons. I have always had a penchant for many topics which Dan Brown touches on including religion, renaissance art, the history of the Knights Templar and their subsequent slaughter and supposed integration into the Freemanson society so I wasn't surprised that I was entertained.
As soon as I finished the book, I instantly began thinking about how it might fair as a major motion picture - how visually, the right director could take full advantage of the inherent beauty of the the various European cities and personalities depicted, possibly flashbacks to Da Vinci's time, the religious passions involved, etc. Well, now a couple years later I must say that I am fairly disappointed with the final execution. For those who are die-hard fans of the book (and their are many) I believe they will enjoy the film on some level, but the film is really flimsy unless you've first read the book. Ron Howard made the choice to leave out so much content from the book that I considered important to the development of the characters and of course the various back histories involved. I felt a bit cheated as I walked out of the movie theater... in almost the way that I felt I cheated myself by choosing to read "Cliff's Notes" synopsis of great books back in high school.
As for the casting, Tom Hanks was a mistake - plain and simple. He is not Robert Langdon and should not be considered for the role of Dr. Langdon if "Angels and Demons" makes it the silver screen (I'd rather see a Forest Gump II, thank you!). I thought Ian McKellen could have been perfect for the role, he is actually exactly who I had imagined for the role of Sir Teabings as I read the book. Poor character development in the FILM, not the book killed what could have been a very good performance. I concur with Goatofthenever - Jean Reno IS Fache, excellent performance on his part. I also agree that Audrey Tautou was a great choice, and I too have loved her ever since "Amelie" but I felt that similar to McKellen's performance, it was hindered significantly by the shallow script.
Oh well.

Like many others have said before, the beauty of what Dan Brown has created is not so much in the book or (heaven forbid) the film but the newfound sense of curiousity that many people worldwide now have about the religious and historical events that make up our understanding of the evolution of modern society and the many faiths therein.