My favorites:
Gilgamesh (FSN)
Kazamatsuri Miyabi (Harukani Aogi Uruwashi no)
Reinhard Heydrich (Dies Irae)
Reinhard von Lohengramm (Legend of Galactic Heroes)
Tohsaka Rin (FSN)
Others I loved:
Akiha Vermillion (Tsukihime)
Katori Rea (Parfait)
Kawashima Himeyo (Sekai de Ichiban Damena Koi)
Kiriya ‘Hime’ Erika (Tsuyokiss)
Makoto Shishio (Rurouni Kenshin)
Ursula Fleur Janmell (Tsuki ni Yorisou Otome no Sahou)
Urumi Kanzaki (Great Teacher Onizuka)
Others I liked:
Akazawa Izumi (Another)
Anima (MinDeaD BlooD)
Ar Ajif (Demonbane)
Asakura Naoko (Kono Aozora ni Yakusoku wo)
Asch Fon Fabre (Tales of Abyss)
Asuka Langley Sohryu (Neon Genesis Evangelion)
Azai Gonzo (G-Senjyou no Maou)
Chroche Latel Pastalie (Ar Tonelico II)
Etna (Disgaea)
Fujibayashi Kyo (Clannad)
Furude Rika (Higurashi)
Galahad (Cannonball)
Hanagusuku Atori (Rui ha Tomo wo Yobu)
Higuchi Ririko (Sharin no Kuni)
Hino Rei (Sailor Moon)
Itami Karura (Ore-tachi ni Tsubasa ha nai)
Kawashima Ami (Toradora!)
Kokudou Kyouka (Akatsuki no Goei)
Kuki Hideo (Maji de Watashi ni Koi Shinasai)
Kuonji Shinra (Kimi ga aruji de)
Lambda-Delta (Umineko)
Legretta (Tales of Abyss)
Liliane Vehlendorf (Mana Khemia 2)
Lishiya (Aiyoku no Eustia)
Louise Francoise le Blanc de la Valliere (Zero no Tsukaima)
Matou Shinji (FSN)
Mello (Death Note)
Miyazawa Yukino (Kareshi to Kanojo no Jijou)
Nagoshi Michael (Owaru Sekai no Birthday)
Oshino Shinobu (Bakemonogatari)
Sasasegawa Sasami (Little Busters!)
Sawachika Eri (School Rumble)
Seifer Almasy (Final Fantasy VIII)
Shana (Shakugan no Shana)
Shimidzu Mio (YU-NO)
Sonohara Daigo (MinDeaD BlooD)
Tokita Yuki (G-Senjyou no Maou)
Uehara Anko (Great Teacher Onizuka)
Viconia (Baldur’s Gate)
Visual novel & other stuff impressions 