Favourite male vocalist is Daniel Tompkins. His style has changed a little bit with recent releases to become a little bit softer and more processed but he's responsible for some of the best vocal performances on songs that I've ever heard. Amazingly beautiful voice and also an incredibly powerful scream for metal music (also I have a man crush on his face and he was the reason I got my hair cut the way I did back in the day >.>)
Favourite female vocalist will probably always be Carina Round. I don't like any of the work she does with puscifer these days and she's a lot different now to what she was back when I was obsessed with her music. However she was too large a part of my musical influence to ever fall from that top spot. Also, her lyrics from her first two albums are absolute perfection.