I wont see the movie because I have already read Holy Blood and Holy Grail years ago and it is just a rehash. I also don't support Hollywood much anymore.
Ah, but there's a big difference! I, too, read HBHG when it came out, '83, I think. As a student of world history, it helped explain a lot, particularly how secret societies in Europe sustained a legend that helped make and depose kings, explain 'Divine Right', and allowed a handful of 'somebodies' to play puppet-masters down through the centuries -- all the while remaining somewhat on the outs with ecclesial authority. The mysterious themes by Poussin, et. al., concerning the partial phrase, "Et en Arcadie, ego...", the skull and bones of Magdalene -- all these seem reminiscent of conspiracy theorists' musings of today, along the lines of Skull and Bones Society, Trilateral Commission and Council on Foreign Relations.
I said all that to say this: Baigent and Leigh simply put two-and-two together to detail a long-standing conspiracy by king-makers, mover-shakers, without commenting on the veracity of the central Jesus/Magdalene legend. In fact, I found them looking at the premise with a jaundiced eye. They theorized, rather, that the legend was a pretext for power and control. The incorporation of important, wealthy people into the secret orders was a way of augmenting sustaining that power and control.
The monumental difference with Dan Brown's piece is that it proffers the legend as fact. And WHAT a difference that is! If true, it renders Jesus, the Church's One Foundation, the very Son of God, God Himself, a liar and a charlatan, not just ordinary, but despicable. If that's the real Jesus, then He would not even be worth talking about!!!! Not at this late date. It would be like continuing to be in awe of the Wizard of Oz after paying close attention to the man behind the curtain.