Day 4 - Favorite episode
If you know my love for Buffy and Angel, then this should come as no shock: "I Will Remember You" - I literally cried when Angel told Buffy that he was erasing that day. The episode is also one reason that I can accept a Buffy and Spike relationship. Angel and Buffy belong together and the only reason they're not is due to his curse....I so wished Buffy would have remembered the day..it's the one thing that depresses me when it comes to both shows.
Honorable mentions would have to include: "Hero" and "You're Welcome" =)