There Will Be Blood is full of great scenes. It's an incredibly well made film.

My favorite is probably the confession scene. DDL's acting in it is top notch. The looks Daniel gives the preacher as he's forced to confess, the look after the first slap, how he shakes off the holy water and quietly says "for the pipeline".
[youtube]https://www.youtube.com/watch?v=jBYTKsYTn5o[/youtube]