I've heard that the reason Joss Whedon wrote this episode was because critics were saying that the actors in Buffy can't act, and that the success of the show was purely based on the shows cheesy dialogue. So, he wrote this episode, and it was nominated for a bunch of awards, if I'm not mistaken... looks like he showed them!
This is by far my favourite episode of Buffy. My favourite scene is the beginning, when Buffy is having her prophetic dream, and she turns around to see one of the Gentlemen standing behind her. That quick flash scared the crap out of me.
Also, the last scene with Buffy and Riley, when they "need to talk".. they were forced to be silent by the Gentlemen for the last however long (couple of days?), they finally have their voices back, and can't think of a word to say. GENIUS!