What exactly constitutes a 'yellow' coaster is an interesting question. Personally, I would say the color of the track defines the color of the coaster.
If I'm at Busch Gardens with my friend and telling him about the Loch Ness Monster, and he asks which one it is, I'm not going to say "It's the hunter green one with yellow track." Whereas if I were to just say "It's the yellow one" without defining whether I was talking about the track, the supports, the cars, the station, or what have you... he would know precisely which coaster I was referring to.
Even Top Thrill Dragster, which has way more yellow paint than red paint, would still probably be referred to by most people as "that big red coaster."
That being said, I feel like it's kind of cheating to lump coasters with yellow supports into this discussion. I also wouldn't consider Dominator at KD either, since only one element is yellow. Rides like Talon, Silver Bullet, and Mantis are weird, but since their spines are yellow and that's the most visible part of the track, I'd still call them yellow. If their paint schemes had been reversed, I'd call them orange/red.
So I would guess the best yellow coaster in the world is probably Kawasemi or Eagle Fortress, but to rank those that I have ridden:
1. Volcano
2. Georgia Scorcher
3. Mantis
4. Loch Ness Monster
5. Wicked Twister
6. Python (BGA - closed now)
7. Ricochet