Voice Actors:
Kyo Kusanagi: Masahiro Nonaka
Benimaru Nikaido: Monster Maetsuka
Choi Bounge: Monster Maetsuka
Ralf Jones: Monster Maetsuka
Goro Daimon: Masaki Usui
Ryo Sakazaki: Masaki Usui
Terrance Bogard: Satoshi Hashimoto
Kim Kap Hwan: Satoshi Hashimoto
Andrew Bogard: Keiichi Nanba (Did Zoicite from Sailor Moon)
Joe Higashi: Nobuyuki Hiyama (Didn't he do Shoma from Rival Schools?)
Yuri Sakazaki (Yurance): Kaori Horie
Robert Garcia: Mantarou Koichi
Takuma: Eiji Tsuda
Heidern: Toshimitsu Arai
Rugal Bernstein: Toshimitsu Arai
Leona Heidern: Masae Yumi
Vice: Masae Yumi
Iori Yagami: Kunihiko Yasui
Mature: Hiroko Tsuji
Kasumi Todo: Masae Yumi
Clark: Yoshinori Shima
Athena '98: Haruna Ikezawa
Sie Kensou: Eiji Yano
Brian Battler: Eiji Yano
Heavy D!: Tosikazu Nisimura
Chin Gentsai: Tosikazu Nisimura
Chizuru Kagura: Akiko Saito
Lucky Glauber: Key Inage
Mai Shiranui: Akoya Sogi
Chang Koehan: Hiroyuki Arita
Yashiro Nanakase: Makoto Awane
Shermie: Hazuki Nishikawa
Chris: Rio Ogata
Ryuji Yamazaki: Kouji Ishii
Billy Kane: Atsushi Yamanishi (I could swear this guy does other Fatal Fury voices...)
Saishu Kusanagi: Keiichiro Sakaki
Shingo: Takehito Koyasu (Can we say "Daisuke" from the japanese Ranma 1/2? Maybe a guy from pokemon or Kayin Amoh from the Battle Arena Toshinden anime...)
King: Harumi Ikoma
Mary: Harumi Ikoma (She also does the round announcement in KOF 98 as well as voices for Charlotte and Nakoruru in Samurai Shodown).
Grabbed a little info from Gunsmith's Seiyuu FAQS (forgot some name spellings etc.) so i'm gonna acknowledge that here (maybe drop him a line). Also got help from, (of course), the KOF game ending credits.