I think the best of the best are pretty evident. I'll shout out The Silence of the Lambs though.
I'll note my FAVORITE win is probably Parasite in the sense that is was completely deserving but I didn't think it would actually happen. My personal tastes rarely line up with the actual winner.
These two are real standouts to me not just on merit but on the fact that they're a type of movie the Academy rarely recognizes — somewhat gnarly thrillers.
I'll throw in a plug for All About Eve and Amadeus too.
As for bad, I don't hate CODA, but it's one of the blandest and most forgettable winners ever. It's like saying the best dessert is a plain scoop of vanilla ice cream. I've never been a fan of The Artist, which is another one that picked up the big award and then seems to have been immediately memory holed. I think Million Dollar Baby and A Beautiful Mind are bad movies.
And I know it's going to take shit here as a bad movie (because it always does), but Shakespeare in Love is good.