Dune is a seminal, evergreen work of the genre. I think its as inspirational to fantasy novels as it is to epic SF novels in its scope, plots, characters and style.
Another classic. A masterpiece of world creating. The spice, the Fremen culture, the sandworms, the Bene Gesserit and the Spacing Guild. I would love to see a new film interpretation.
Another one of those must reads for 'real' SF fans. A novel that gave rise to the term 'ecological science fiction'; and a novel that has been much-maligned by the never-ending series of sequels. This is a true HEROEs journey tale (you can map Homer to it pretty well) with some amazing world-building.