Judge Zargabaath; I love honorable villains and he's great. He's also one of the most sensible and levelheaded Judges. Plus it's Simon Templemen's voice (who was Kain in the LOK series)!

I also liked Judge Drace, but she had precious little screen time. I have a weakness for Valkyrie-type warriors (like Agrias and Beatrix). A boss fight against her was (SPOILER)too much to hope for I guess.