I had a really hard time deciding ^^;;
I wanted to vote for Toshi... but I'm on a sudden Hyde kick so I couldn't resist voting for him. I love his voice in the soft songs, like Evergreen. He has such power... like in Cape of Storms... anyway. That's my vote.
And Klaha was the other vocalist of Malice Mizer, aside from Gackt. He sang Gardenia, Beast of Blood and the post-Gackt stuff.
Now, is he the vocalist of Moi dix Mois? I never found out.