Probably Prophecy Girl. It's where I tell my friends to start watching the show. I watched WTTH and wasn't interested, then gave Prophecy Girl a chance when it popped up on a download community I frequent, and have been hooked ever since. Season One as a whole isn't my favorite, though some episodes are so fun to rewatch.

When She Was Bad is one of my top 10 episodes. I think I'm weird in that I prefer that to School Hard.

P.S--I've seen you around in different Buffy journals/communities. Friending you if that's okay.