Dune (first book only), The Fountains of Paradise by Arthur Clark, Robert Heinlein (Starship Troopers, The Moon is a Harsh Mistress, Stranger in a Strange Land)

Dune (first book only), The Fountains of Paradise by Arthur Clark, Robert Heinlein (Starship Troopers, The Moon is a Harsh Mistress, Stranger in a Strange Land), Uplift Series by David Brim, The Mars Trilogy by Kim Stanly Robinson, Ann Leckies books are really interesting new sf.