I read a lot of books in my life, and I should note that I almost read all the sci-fi/fantastic zone of my town library -.-
but my favorite sci-fi writer is Alastair Reynolds, his books are bricks, but they're fun... to continue with sci-fi, the Dunes series are one of the best of all times, they're almost a dozen of books just in the Dunes Universe.
As for fantastic: Terry Brooks, David Gemmell, Terry Goodkind, James Herbert are easy read and really entertaining.