I'm currently rereading my Sandman TPBs. I'm a Vertigo nut in general, but my favorite will always be the Sandman graphic novels. I'm planning on starting Hellblazer then Fables.
Right now I'm reading King Rat by China Mievelle. SO recommended if you like dark fantasy set in modern times. China is a brilliant writer, one of my strong influences.
Nobody mentioned Dune yet? For shame! :p
All of Frank Herbert's books are great, but avoid the later stuff by his son. They raped his father's works.
But if you want to know the greatest science fiction author of all time, there is but one man, my idol: