The best lines are all from Dr. Loomis (Donald Pleasence), such as:
“Death has come to your little town, Sheriff.”
“He's gone! He's gone from here! The evil is gone!
“He got hungry.” [staring down at a dead dog]
“I spent eight years trying to reach him, and then another seven trying to keep him locked up, because I realized that what was living behind that boy's eyes was purely and simply...evil.”
Honorable mention: Laurie Strode –“The keys...the keys!”