All Good Things was a great double episode, but we all knew it wasn't the finale and didn't really feel like one. Endgame was pretty crap. Good SFX, the stuff set in the future was interesting, but then it all went downhill. Can't consider Turnabout Intruder a true finale. TATV..... never mind.
So, to me, that leaves What You Leave Behind. Yes, the episode had flaws, sure some thing felt a bit rushed. But I've seen it a few times now, and it still gets me. The