DJANGO MISCATEGORIZED: A separate note: under no circumstances should Christoph Waltz have been nominated in the Best Supporting Actor category; he is clearly the co-lead of the film, and he, not Foxx, carries most of it. According to Joe Reid, who has compiled a solid list of 14 Supporting Noms That Were Actually Leads (see, esp., Martin Landau in Crimes and Misdemeanors), "Waltz was actually being campaigned as a lead in Django Unchained until the critics groups (who should know better) started tipping their hand that he might stand a better shot as a supporting contender."
One that I think Reid gets wrong, however, is Albert Brooks in Broadcast News. Yes, he's in the movie quite a bit, but it's not a movie about him or one which he carries—it's about Holly Hunter and her choices, and [SPOILER FOR A MOVIE THAT'S NOW 25 YEARS OLD]
as much as Brooks' Aaron Altman thinks he's in a romantic triangle, he's not. She was never going to choose him, or see him as anything other than Friend Material. Now, as to whether William Hurt also should have been categorized as Supporting as well as opposed to the Best Actor nomination which he did receive, I think that's open to debate. He's got more of an arc than Brooks has; it's his actions which set things in motion.
Final note: Broadcast News lost all seven Academy Awards for which it was nominated. Boo.