The title of this thread speaks for itself, really. There are some lines of dialogue that just stay in your memories forever, either because they were funny, well-timed, witty, corny, powerful or just plain EPIC.
What better way to start this thread, than to quote Darth Vader in The Empire Strikes Back?
Darth Vader: No. I am your father.
Luke Skywalker: NOOOOOOOO!!!
- Star Wars: The Empire Strikes back