I found the Ainulindale to be one of my preferred parts, but I'm also the kind of person who would enjoy reading Hesiod or the Bhagavad Gita as well. I enjoy religious literature without the bother of agreeing with it; it has a different quality that mercilessly bends the strict fiction/non-fiction line we like to pretend exists.

I actually read it while I was young and hadn't the money to buy my own books: I got it as a single, enormous Word document from a friend and read it by CRT display.