My favorites:
Kurata Sana (Kodomo no Omocha)
Others I loved:
Cal Devens (Phantom of Inferno)
Don Pachi (Bobobo)
Illyasviel von Einzbern (FSN)
Miyamura Miyako (ef -tale of the two-)
Naegino Sora (Kaleido Star)
Onizuka Eikichi (Great Teacher Onizuka)
Rinoa Heartily (Final Fantasy VIII)
Others I liked:
Aino Minako (Sailor Moon)
Amemiya Daigo (Himawari)
Beatrice Kircheisen (Dies Irae)
Hojou Marina (Eve -burst error-)
Kanan (Last Story)
Karube Karuo (Ore-tachi ni Tsubasa ha nai)
Katori Yui (Parfait)
Laguna Lore (Final Fantasy VII)
Luca Truelywaath (Ar Tonelico II)
Minazuki Sora (Baldr Sky)
Nandaba Kamon (FLCL)
Nikaidou Aoi (Itoridori)
Noda Megumi (Nodame Cantabille)
Peperoncino (Mana Khemia 2)
Philomelle Hartung (Mana Khemia)
Sakihata Rimi (Chaos;Head)
Selphie Tilmitt (Final Fantasy VIII)
Shinobu Morita (Hachimitsu to Clover)
Tanaka Yubiseiharukana (Ever 17)
Tanomura (Swan Song)
Wolfgang Grimmer (Monster)
Yuzuriha Nekoi (X TV)
Visual novel & other stuff impressions 