I just can't think of anyone at all for Hikki. She's done the R&B thing like Aaliyah, experimental music like Bjork, and electronic/dance like Britney or Madonna. She's also got this boyish thing that almost reminds me of rocker chicks like Karen O and PJ Harvey. She's got so many different facets of different artists, maybe that's why I love her so

As far as Madonna / Ayumi comparisons... I don't see it at all. I know they're both the Queens in their respective countries (although that's becoming debated for both), their careers are soooooooooooooooooo different. Madonna has more in common with Kuu in my opinion.

I don't know if I see the Misia = Mariah comparisons. Misia has absolutely no soul in her voice, although she has a great set of pipes. I don't see her as hypersexual and Mariah, either, and she doesn't have the hip-hop chick status that Mariah does. Her success isn't that impressive, IMO, either, whereas Mimi is the best selling female artist in the US in the past 25 years.

While I know the artists don't match up, I think the Ayumi/Utada rivalry has a lot of similarities to the Mariah/Madonna rivalry. Two ladies battling for the crown!