Lord of Light is absolutely brilliant is definitely up there with Dune as the greatest sci-fi novels ever written (it is interesting to note that Zelazny's first novel, This Immortal, tied with Dune for the Hugo Award they year they came out). I love Zelazny's ability to take mythology/religion and incorporate it into a sci-fi setting. In Lord of Light he uses Hinduism and Buddhism, in Creatures of Light and Darkness its Egyptian mythology, in This Immortal its Greek mythology, and he even uses Native American mythology in Eye of Cat. If you haven't read it yet, I highly recommend it. Maybe I'll write a review of it and post it.