Deep Down.
It's also in my top five best episodes, it's just brilliant; it has everything. It's a great introduction to the season about to come and all the scenes do their job, Connor with Gunn and Fred, Angel's hallucinations, and I love how we get to see that, sure, Wesley has kinda lost his way a bit (sleeping with the enemy, slave girl in the closet) but he's still Wes and goes out of his way to save someone who, last time he saw him, tried to kill him. I can't even pick a favorite scene, cause there are so many good ones, like Angel hallucinating the dinner scene before it turns, or Wes and Justine on the boat having their talk before they find Angel, or Angel confronting Connor at the end and sending him away.
It's got one of the best quotes from the show, too; "Nothing in the world is the way it ought to be. It's harsh...and cruel...but that's why there's us...champions. It doesn't matter where we come from, what we've done, or suffered. Or even if we make a difference. We live as though the world were as it should be, to show it what it can be. You're not a part of that yet. I hope you will be."