The original Dune series (the 6 books actually written by Frank Herbert) are great. Dune is an amazing book, and while the other 5 aren't quite up to its level, they are all compelling reads, with great plots. All 6 are books that I feel everyone should at least try to read. Personally, I prefer them to even Lord of the Rings.
Unfortunately, Brian Herbert and Kevin Anderson couldn't continue the greatness of the originals with the Dune prequel books. If you loved the originals, the prequels are good just for some background information, but they never even approach the greatness of Frank's writings.
As to the movie, it's horrible. Maybe worth watching out of intrest , but nowhere near good as the books. It butchers the storyline of the books so horribly that it almost made me cry.