I've only watched the first season, and these have been my favorites:
The Lonely Time Enough at Last Perchance to Dream Third from the Sun I Shot an Arrow into the Air The Hitch-Hiker Elegy The Monsters Are Due on Maple Street Execution A Nice Place to Visit A Stop at Willoughby The After Hours A World of His Own
"Fire cannot kill a dragon." -Daenerys Targaryen, Game of Thrones