Voices, too.
Love, Really Like, Okay, Meh, Dislike
1st Gen: Yuko, Aya, Nacchi, Kaori, Asuka
2nd Gen: Kei, Mari, Sayaka
3rd Gen: Maki
4th Gen: Rika, Yossie, Tsuji, Kago
5th Gen: Ai, Konno, Makoto, Gaki
6th Gen: Miki, Eri, Sayumi, Reina
7th Gen: Koharu
8th Gen: Aika, Junjun, Linlin
9th Gen: Mizuki, Eripon, Riho, Kanon
10th Gen: Haruna, Ayumi, Masaki, Haruka
Kinda hard to rank the 10th gen, though, when I haven't heard them that much.
And voices for other H!P groups:
Berryz Koubou: Captain, Momoko, Chinami, Maasa, Miyabi, Yurina, Risako
C-ute: Maimi, Nakki, Airi, Chisato*, Maimai
S/mileage: Ayaka, Yuuka, Kanon, Saki.
Soloists: Mano
* Only when she's singing in her natural voice, not her forced high-pitched cute voice. >_>
Aaaand members for the H!P groups:
Berryz Koubou: Captain, Momoko, Chinami, Maasa, Miyabi, Yurina, Risako
C-ute: Maimi, Nakki, Airi, Chisato, Maimai
S/mileage: Ayaka, Yuuka, Kanon, Saki
Soloists: Mano
Edit
Just realized that I forgot Yurina. Oops.
Edit 2
And Asuka. >_> This is what I get for doing everything from memory. I wonder who else I forgot...