i dont know about spain, but in spanish language, there are two groups of famous writters a) the respectable ones b) the production ones! so, if you are looking for good literature. Jose Saramago(thouh he is brazilian, he also write in spanish), Gabriel Garcia Marquez (GABO from Colombia) and so on. But this two still alive!

Well, the 2 Reiman recomended are good, even Saramago is from Portugal, he has a perfect knowledge of Spanish. With García Marquez you can learn the way Spanish is spoken in America. If you want some Spanish wraiter Ruiz Zafon with "La sombra del viento" gained a great reputation as his started out of the comercial net. But to recommend something most especific i need to know what are you interested in, or what kind of books you like reading .