1. Ayu
2. Namie
3. Mika Nakashima
4. Koda Kumi
5. Do As Infinity
jfc it's so hard to pick just 5. I would say that positions 2-4 rotate among those 3 artists depending on my mood, and #5 also changes.
Right now it's DAI, but sometimes it's Miliyah or someone else. urghhhhh I just can't commit