First, no K-pop. I'm looking exclusively for Japanese music.
I'm looking for stuff that's not too bubblegum/cutesey. I like some stuff like that, but I'm looking for stuff that's different. I heavily prefer female vocalists. In general, I like rock, metal, electronic, jazz, and classical. With very few exceptions, I don't like hip-hop or r'n'b.
Let me list stuff I like and maybe you can recommend similar stuff:
Other stuff I like to some degree, but not as much:
Malice Mizer (the vocals mostly don't do it for me, but Mana-sama is awesome)
Moi Dix Mois (same, except I like the music better)
Perfume (pretty new to their stuff, but they seem pretty good)
Kyarypamyupamyu (cool, but a little too upbeat and cute at times--depends on my mood)
AKB48 (specifically, I like the song Beginner--the rest seems too bubblegum/cute for me)
Utada Hikaru (I like her voice, but a lot of her music doesn't really do it for me)
Dir en grey (sounds a little too nu-metal at times, but overall quite good)
Queen of Support
Please use the Music Recommendation thread.