The Hyperion Cantos, which is made up of four books, Hyperion, The Fall of Hyperion, Endymion, and The Rise of Endymion.
I haven't read them for a while, but I'm rereading them. All I remember is that it is the most epic sci-fi story ever told. It'd be like if John Keat's poetry, Canterbury Tales, Lord of the Rings, and Isaac Asimov had a baby. Then that baby became god and created a perfect universe. That would be the Hyperion Cantos.