My favorites:
Kouyama Mitsuki (Full Moon wo Sagashite)
Lacus Clyne (Gundam Seed)
Others I loved:
Aerith Gainsborough (Final Fantasy VII)
Amagi Yukiko (Persona 4)
Faina S. Shinozaki (Infinite Ryvius)
Himura Kenshin (Rurouni Kenshin)
Hinata Natsumi (Sharin no Kuni)
Kazuha Shizuha (Haru Made, Kururu)
Kujiyou Miya (Kono Aozora ni Yakusoku wo)
Mizumori Minami (Soshite Ashita no Sekai yori)
Ototsu Yume (Hoshizora no Memoria)
Sephiroth (Final Fantasy VII)
Shurelia (Ar Tonelico)
Takizawa Tsukasa (Harukani Aogi Uruwashi no)
Valerian Trifa (Dies Irae)
Others I liked:
Alice Elliot (Shadow Hearts)
Arima Soichirou (Kareshi Kanojo no Jijou)
Chichiro (Persona 3)
Emiya Shirou (FSN)
Fall From Grace (Planescape: Torment)
Flonne (Disgaea)
Fujiwara no Sai (Hikaru no Go)
Garnet Til Alexandros 17th (Final Fantasy IX)
Ichinotani Touka (Ayakashibito)
Jinmu Miyaka (Extravaganza)
Kururugi Suzaku (Code Geass)
Kusanagi Shiyuu (X TV)
Lapis (Genrin no Kishogun 2)
Monou Fuuma (X TV)
Nia (Tengen Toppa Gurren Lagann)
Qvon (BALDR FORCE)
Rakka (Haibane Renmei)
Tsukamoto Yakumo (School Rumble)
Walter Sullivan (Silent Hill 4)
Yukishiro Tomoe (Rurouni Kenshin: Reminiscence)
Yuna (Final Fantasy X)
Yuzuha (Utawarerumono)
Visual novel & other stuff impressions 