It's interesting how people take in a movie but here is my take, which is probably more of a reflection of me. My interpretation of Daniel Day Lewis' character, Daniel Plainview, is that of a misanthrope - so jaded, but not feeling sorry for himself, he moves forward by dealing in the world of oil and money. You know nothing of his background except that he's focused on getting something of value & satisfaction in his life (so help him God). He was someone who always saw the absolute worst in life and in people, but yet, he still had that thread of hope deep inside to believe that maybe there was some truth in the good of life - of love, hope and beauty. It looks like he almost succeeds with his love for his adoptive son, but in the end he shuts the door on him (so jaded). The preacher (who played the son in "Little Miss Sunshine" of all things) speaks so heart true in his role of speaking of the glory of God and spirituality. He eventually sells out, which unfortunately, causes his death by you know who. It was a great movie and Daniel Day Lewis is an awesome actor. I'm surprised that the guitar was done by Radiohead's Jonny Greenwood. The music is so wierd, yet so engaging.
"There Will Be Blood" is far different from "No Country for Old Men" - by novelist Cormac McCarthy. Javier Bardem's character, Anton Chigurh, is a cold blooded executioner who lives by, of all things, a moral code. He does not see any beauty or joy in life except for his own purpose in life (torturer, killer, Death's administrative assistant of those who betray this code). He is impartial to everything except his own code of killing. You never want to see him, for to see him is to die.