I was all about Yukiko in vanilla and never got the hate for her that so many seem to have (oh noes a shy feminine girl, evil!) but in Golden I'm all about Marie.
Marie end game spoilers:
My Goddess girlfriend.
How can anyone hate Yukiko? She hardly has any negative qualities. Sure, she can be boring, but to actually dislike/hate her... why? --- Square Enix, create a sequel to TWEWY. You have 3 years. Fail and face erasure. - The Fanbase http://www.youtube.com/watch?v=fjf48W3Dg98