Just watched Django Unchained; different gravy.
Having watched it, I can understand why Leo wasn't nominated. He was only introduced halfway into the film, and his performance wasn't spectacular enough to garner a nomination, it really would have to be amazing for him to be nominated considering the percentage of screen-time he had. Having said that, Christoph Waltz really could be nominated for Best Actor, he played the lead for 80%+ of the film, and was great.
Definitely rooting for Django to win Best Picture, although it seems an impossibility seeing as Tarantino isn't nominated for Best Director, which usually means it won't score enough votes to win Best Picture. I'm sure Christoph Waltz will pick up his award though, and maybe Tarantino for Original Screenplay.