Wha's the best acted scene from a movie ever?

Impossible to answer. There have been so many. To give it a twist I'd nominate Michael Kitchen, not for a siingle scene, but for the title role in the  BBC series "Foyle's War". His face is so expressive that the merest twitch of an eyebrow could take the place of many words.

Christian Slater from Heathers.

In my opinion, the coronation scene from The Chronicles of Narnia: The Lion, The Witch and the Wardrobe has great acting. Or come to think of it, any scene in general is really well done in that movie. 

Al Pacino: "scent of a woman"

The speech in the courtroom.."whooooahhhhh"