Tori Amos has astounded me every time I see her.
And Lacuna Coil is a split decision: Cristina is amazing (in many ways...), but I really can't figure out why Andrea is in the band. Hopefully it's not because of his songwriting ability, as I find they are getting more and more derivative as time goes on. But Cristina... oh Cristina. LOL
Also, I have to give a mention to Raine Maida of Our Lady Peace. When they first came out, I heard a live recording of Naveed on the radio, and I felt physical pain it was so bad. Later on I went to a festival they were headlining, and was walking to the car when they came on. I was too tired to walk back to the festival grounds, but I leaned against my car and listened to the whole set, it was incredible. I've seen them at least a dozen times since, and they've always blown me away.