With this pick I draft, Loreena McKennitt.
She's quite possibly my favorite vocalist. I've been a big fan every since "Mummer's Dance" was a minor hit in the late 90s.
Her angelic voice is the main attraction but she's also quite a good producer and arranger/composer. She plays the harp, piano, and accordion, as well.
Her blend of Celtic, renaissance, and world music makes great mood music. Great for turning up and just relaxing to when I want something different from the rock, metal, pop, etc. I usually listen to.