Intervention has got to be one of my favorite episodes in the series. The Buffybot is hilarious, Spuffybot scenes are both funny and a little pathetic because Spike wants them to be real so much, and the Spuffy kiss at the end is *golden.* It adds such depth to the character (arguably, even more than Fool For Love), and it really is when we realize that Spike cares for Buffy and her well-being. That point was brought home at the end of Fool For Love, but not as strongly. Intervention is the perfect mix of hilarity and poignance. The only thing that could have made it better was a one of those scenes where we see someone playing at The Bronze and then it keeps flashing to our characters being all alone and contemplative. I know there's a word for that, but it's not coming to me right now.
Other great ones are The Gift (of course), The Body (of course of course), and Listening to Fear. This episode just creeps me out so much. I think it has something to do with the Queller on the ceiling. If the creature is on the ceiling, it makes it that much creepier! Joyce's dementia is also extremely creepy. Over all, I think it was a wonderfully done episode that really hit home what a dire situation Joyce (and Buffy) was in.