There is so much about this episode, despite being a 'set up' episode that is so good. It starts a little slow with Angelus just stalking again, but from the time that Kendra shows up until the slow motion run of Buffy down that school hallway, knowing that something horrible has happened, its just non-stop.
The highlights: Angelus vs. Spike in the snark contest, the confrontation with our gang concerning Angel's resouling (especially the Xander/Buffy/Giles argument):
Giles: Curing Angel seems to have been Jenny's last wish.
Xander: Yeah? Well, Jenny's dead.
Giles:(approaches Xander angrily) Don't you *ever* speak of her in that tone again!
Xander: yells back) Can't you hear what I'm saying?
Buffy: Stop it! Stop it!
They all shut up and glare at each other for a moment. Buffy turns away and goes over to Willow, very upset. Giles paces away, also very upset.
Willow: quietly) What do you wanna do?
Buffy: (sighs)I don't know. What happened to Angel wasn't
Xander: Yeah, but what happened to Ms. Calendar is.
Buffy and Willow stare at him in disbelief.
Xander: (angry) You can paint this any way you want. But the way I see it is that you wanna forget all about Ms. Calendar's murder so you can get your boyfriend back.
The attack on the library while Angelus is keeping Buffy occupied is also exciting and disturbing. Special mention should go to the wonderful music during this ending segment.