I sure there's going to be a lot to say about Big FAQ 2.
But for now here is a handy chart of all required reading materials to play 40k (Malal and Squats need not apply).
"8th Edition is going to make things so much clearer than 7th guys! We won't need nearly as many books I swear!" -Clueless people on facebook
UPDATE:
A small surprise. I realized after I made this that BIG 1 FAQ has been merged into the other relevant faqs. One less folks!