Dune is by far my favorite fiction series of all time. I re-read the first book at least once a year (and bought the Folio Society's amazing edition awhile back). The religious thinking that underlies parts of it is pretty amazing.
Random question, related to that: do you have an English version of the Qu'ran that you'd recommend? I've read some of A. J. Arberry's translation, which I've heard is stylistically good but not the best in terms of accuracy. Learning Quranic Arabic is on my to-do list, but I've got another language (which I've only just started) to finish first.