10. Buffy Vs Dracula
Capitalising on the free reign the show had at the beginning of season five - before things got heavy (like, Riley-leaving, Mother-dying, Buffy-dying heavy) - the opening episode pitted Buffy against that most fabled of vampires, Dracula, in a one-and-done that nobody saw coming.
Rather than set the tone or villain for the whole series, this unexpected showdown allowed for a bit of camp, tongue-in-cheek fun and shenanigans before getting down to business.
And what's not to love? Xander is the first to become enthralled, praising His Excellent Spookiness and eating bugs; Giles falls (figuratively and literally) for the Dark Lord's harem of sexy vampire sisters; and even Buffy herself flirts with the darkness.
Shenanigans unfold as the gang venture to the large European castle that they've somehow never noticed in Sunnydale before, and the laughs keep coming right until Dracula's final(-ish) defeat, returning from the dead a couple of times in misty form, while Buffy is "standing right here!"