The Bible; I know people usually assume it means I'm religious, but that's simply not the case. It's an interesting book in its own right, and it has had the most meaningful contribution to my life because it's one of the most influential books of all time. Reading it grants one better insight into art, cinema, literature, music, etc. etc. etc. Even creations that disagree with it have been influenced by it - obviously, since they disagree with it - so reading it allows you to understand why someone disliked the book. You also expand your vocabulary by reading it. And the stories in it are generally very interesting; it has its dry parts obviously.
I believe it's the most bang for your buck, or I guess bang per number of pages.
I'm coming to appreciate the bible and its evolution. My latest appeciation? The KJV's translation biases (I don't want to say 'errors') makes me want to look at the Torah, which also has it's own evolution (or lack there of).
Of English translations, yes the KJV. But I'm Serbian, so I primarily read Serbian translations, or a bilingual Bible, side by side KJV and Daničić-Karadžić translation.
As for the translation biases, that's kind of a separate topic, and comparing translations is very interesting for me personally, I enjoy using that AndBible software.
Apocrypha too has interesting stories which influenced art, literature, etc. etc. etc. Definitely worth reading.
A side note, since you mention the biases, I think you might enjoy the book development of the New Testament canon, I don't remember the author or the exact book title, sorry about that. I find it fascinating that the only books of the Bible whose author is confirmed are seven pauline epistles (perhaps three more, I think yes, but I'm a layman). I could go on, but I have to stop somewhere.
