Yamaguchi Kappei
He also did Jin's voice for Yu Yu Hakusho, White Prince from Akihabara Dennou Gumi, Kimiira of B'T X, Noda Yuuya of Miracle Girls, Kasama Haruhiko of Please Save My Earth, Etoh from Record of Lodoss War. Musashino Yasuharu from Rurouni Kenshin {Ishinshishi he no Requiem}, Tenkuu no Escaflowne's Shesta and Takurou of Wedding Peach. He's got a great voice that he can easily use to sound funny, serious, and even freakishly innocent (check out Haruhiko!). He's my all-time fave male seiyuu (isn't it obvious?)
Hayashibara Megumi
One of female favorite seiyuu, Megumi-san did as far as I can remember, 111 anime roles. Including young Genkai from Yu Yu Hakusho, Lime of Saber Marionette J, Pai of 3x3 Eyes, Fujimiya Momiji of Blue Seed, Ayanami Rei and Ikari Yui of Evangelion, Canal Volfeed from Lost Universe, Rihoko from Ninku, Amano Ai in Video Girl Ai, Nuku Nuku in Cat Girl Nuku Nuku, and MANY more. It's so cool how she can make her voice almost as small as Sakuma Rei's, and then again, she's that tomboyish girl screaming the daylights out of some poor guy.
Hidaka Noriko
She has a cool and calm voice, which she can make into a screaming nagger when she wants to. She did Shiine from Akazukin Chacha, Endo Kazumi of TTS Airbats, Seta Soujirou from Rurouni Kenshin.
Takayama Minami
She usually takes roles of strong girls with an attitude, or young boys. She did Mukuro of yu Yu Hakusho, and Yaiba from Yaiba, Dilandau *shiver* and Price Chid of Tenkuu no Escaflowne, to name some. She is also the singer of TWO-MIX, who did songs for Gundam Wing.
Inoue Kikuko
Kikuko has an endearing voice, and she's very good at singing, too. Her roles include Belldandy in Oh! My Goddess, Saginomiya Sakura in TTS Airbats, Lune Venus of El Hazard, Mimori Seira from Kaitou St. Tail, and Panther of Saber Marionette J.
Oubayashi Ryunosuke
Ogata Ken'ichi
He has a firm, commanding voice, though it sometimes transforms into something that'll make you laugh. He has done Jingoro and Kyosuke's dad in Kimagure Orange Road, Ieyasu of Saber Marionette J, Azaka from Tenchi Muyo, and Ataru's dad in Urusei Yatsura.
Yamadera Kouichi
He's Ryoga's seiyuu, too!
I just put his description there...
Sakuma Rei
At first I thought Sakuma-san's voice is really small...then again, I was wrong^^ She always suits the characters she does, and she also has a cute laugh. Among her many roles are Miyama Mizuha from Maho Tsukai Tai, and Sakura from Pokemon..but my favorite so far is her role as Mariemeia Barton from Gundam Wing Endless Waltz.
Seki Toshihiko
Toshihiko has also done Yakushimaru Mikuro of Please Save My Earth, Asuka's dad in Evangelion, Shougo from X, and Matsuda Kousaku of Yawara!...but my favorate, so far, is his work as Duo Maxwell in Gundam Wing (Duo-sama!!!!!)
Tsuru Hiromi
She has also done Hanakoganei Hinako and Puti Anju from Akahibara Denno Gumi, GS Mikami's Mikami Reiko, Ayukawa Madoka from Kimagure Orange Road, and Asuna Kujo from Maison Ikkoku.
Yamadera Kouichi
Heh. What can I say? Kouichi-san's voice *sometimes* makes you feel so sorry for him. Sometimes you'd laugh at his stupidity, sometimes makes u feel irritated in his stubborness...AND he can even be mature. He's a great actor, and he deserves attention (but of course!) Here are some of the many roles in anime that Kouichi did: Igarashi Nachi from Compiler, Kaji Ryouji of Evangelion, Ninja Scroll's Juubei, and Arisugawa Sorata of X.
Nagai Ichirou
He also did Cherry from Urusei Yatsura. Looks like he's destined to play nutty old men with a bald head and an extremely short height.
Asou Miyoko
Suzuoki Hirotaka
I don't really know that much about 'im, but what I can say is, he definitely made Kuno the way he's supposed to be. The proud, egoistic sempai (understatement!) who spouts nothing but stupidity^_^ He also did Inaba of Urusei Yatsura. It's ironic, isn't it? Inaba is such a nice, sweet and quiet character...BUT that's another story.
Shimazu Saeko
For one, she has a great laugh. I don't think anyone can do that laugh as she does. She also did ChiChi from Project A-ko, Sayoko from Maison Ikkoku, and Shinobu from Urusei Yatsura.
Hitouchi Tateno
Chiba Shigeru
One of the most heard voices in anime, Shigeru has played around 65 roles. Somehow, his name always pops up in the credits. He has played the trademark voice and that 8 octave high shriek of Kuwabara Kazuma from Yu Yu Hakusho, Megane from Urusei Yatsura, Yotsuya from Maison Ikkoku, and Hikosagoemon from Saber Marionette J. He is one of my favorite male seiyuu.
Futamata Issei
Ah, yes...the geaky freak...Almost like the obssessed Chibi from Urusei Yatsura. He also did the bumbling Godai Yuusaku from Maison Ikkoku and, ironically, Kaidou in Yu Yu Hakusho. Other roles include Ootaki of Aa Megami-sama and Shinshi Mikiyasu from Pat Labor.
Mitsuya Yuuji
Koyasu Takehito
Here's another great seiyuu. Actually, I can't believe he has such a small role here in Ranma 1/2. He has done a lot of voices including Aya from Weiß Kreuz, Yuji from Burn-up Excess, Hotohori of Fushigi Yuugi, Zechs Merquise in Gundam Wing, Lezo of Slayers, and Yosyo from Tenchi Muyo. Also, he is one of the producers(?) of Weiß Kreuz.
Tsujitani Kouji
He also did Itsuki's voice from Yu Yu Hakusho.