Unless you're living in a bunker beneath the Earth's surface, in which case I congratulate you on your internet service, you're probably aware that the Last Ever Harry Potter Movie has recently been released. Considering the series has made a ridiculously large pile of money that would freak out Smaug, producers are mining children's bookshelves to find the Next Big Thing. Since the release of the first film, way back in 2001, they have tried multiple times. The Spiderwick Chronicles, The Chronicles Of Narnia, The Golden Compass, Inkheart and Percy Jackson. Their may be others, they are just the ones I can remember. Only one has done well enough to continue the series. You'd think they would have learnt by now.
To get a better idea, Roger Corman hasn't attempted a cash-in of his own. He is considered the king of the cash-in, having done Star Crash for Star Wars, Piranha (the original) for Jaws and Carnosaur for Jurassic Park, which he even brought out a week before Jurassic Park. In fact, most attempts to be The Next anything, don't tend to do terribly well. Go to the horror section of a bookstore, and see how many authors are hailed as the Next Stephen King. So far, I have only come across one worthy of such a title.
The main reason I'm going at this, is the top contender seems to be Artemis Fowl. In fact, I first came across this when I heard a film was in development, back in 2003. Personally, I prefer it over Harry Potter, and would love to see an adaptation, provided it's given proper attention, and not just rushed ahead to give everyone their fix of "boy discovering magical world".