Hiii. And... good question.
Probably - definitely - Twelve Kingdoms. Youko is an incredible character, and I loved her journey from overly-mild-mannered schoolgirl to supreme hardass. Beyond that, the art, music, and world lore were all nothing short of stunning.
Requisite honorable mentions (as much as I love Twelve Kingdoms, it feels wrong not to list anything else ;_; ) would have to include Seirei No Moribito, Erased, Madoka, Clannad, Laid Back Camp, Spice and Wolf, and Haibane Renmei. Maybe that's too many? Probably? Ah well.
