ok, my submission for best line in a poker movie is from "The Cincinati Kid"
players are at the table playing 5 card stud. A fill player and Edward G. Robinsone are in a hand. The fill player looks at his notebook, does some math in the book and makes an exact bet of some odd figure. Edward G. calls the bet and the fill player folds, saying "it doesn't mater what I have if he can call me he wins" He then says "you were supposed to fold to that bet, how could you call?" Edward G. answers:
"As the man once said, you paid to see the cards, lessons are extra."