… has three books in Amazon.co.uk’s Top 25 – so how come no one’s trying to emulate his success?

(Tip of the hat to Mugglenet)
That said, the new Jerry Bruckheimer film, National Treasure (which seems to be doing rather well in the US, and opens here on Christmas Day – not sure what the marketing people were thinking there) is a blatant rip-off of the Da Vinci Code. Just look at this review/synopsis from the IMDb:
Obsessed with a legend detailing a massive amount of buried treasure that was hidden by the founding fathers of America 200 years ago, Benjamin Franklin Gates (Nicholas Cage) has spent his adulthood chasing the clues to finding the loot all around the globe. The greatest challenge facing Gates is the final piece of the puzzle: a secret map located on the back of the Declaration of Independence. With help from his tech geek partner (Justin Bartha, the infamous Brian from ‘Gigli,’ and excruciatingly unfunny), and a reluctant government drone (Diane Kruger, ‘Troy’), Gates steals the famed document and sets off to solve the mystery, trying to keep one step ahead of his rival (Sean Bean) and an FBI agent on his trail (Harvey Keitel).
Apparently, producer Jerry Bruckheimer couldn’t stand the success of Dan Brown’s bestseller, ‘The DaVinci Code,’ and decided to make his own version with ‘National Treasure.’ For fans waiting for the literary thriller to hit screens (in 2006), ‘Treasure’ just might be the right type of diversion during the long wait. For everybody else, this treasure hunting adventure is like traveling over the tallest mountains, diving into the deepest seas, and risking your neck at every turn only to find the gold coins at the end of the hunt have chocolate in them.
I think you get the point.
Ooh – apparently it’s been confirmed that Tom Hanks will be playing Robert Langdon in the Da Vinci Code… not sure whether that’s a good thing or not yet.