Best Picture Winners: Ranked and Reviewed

Yes, I've seen all the Best Picture winners, and all of the Best Picture nominees, This is a ranked list from Best--How Green Was My Valley--to worst--Cavalcade

edit 2018, some reordering, It Happened One Night bumped way up.
edit(s) 2019, as a rewatch project (probably lasting about three years I'd guess, at thirty or so a year), I'm returning to many of these for the first time in fifteen years and reordering them as I go. If you see a review on it, it means It's been rewatched and newly evaluated and compared and reranked.