I'm biased since I've not been able to afford to travel to east coast conventions but AX despite the drama and issues the con has had in the past few years, it was the first con I ever went to so it has a special place with me. That said, Fanime and ALA are pretty much tied at number two though I hope to go to Sakura Con next year...
Anime Los Angeles
Potential Future Crossplays
Maki Nishikino (Love Live) - Summer school uniform