I have a lot, so get ready to scroll.
Lunar Edomae, Seto No Hanayome
The mermaid with a superiority complex.

Dante, Devil May Cry Series
The uber-cool devil hunter.

Konata Izumi, Lucky Star
The hardcore otaku.

Minato Arisato (or else named by the player), Persona 3
The silent protagonist who sacrifices himself to save everyone.

Felt, Atelier Iris 2
The alchemist who ain't half bad at using a sword.
Len Kagamine, Vocaloid
The singing program, mirrored image of Rin Kagamine.

Flandre Scarlet, Touhou : Embodiment of Scarlet Devil
The childish vampire who has immense destruction powers.

Taiga Aisaka, Toradora!
The palmtop tiger.

Ikuto Tsukiyomi, Shugo Chara
The flirty, smart, cool yet cat-like shounen.

Potemayo, Potemayo
The moe blob, complete with cat ears.

Yuuka Midarezaki, Kyouza Kazoku Nikki
The calm and gentle "second daughter" of the Operation Cozy Family.

Haku, Spirited Away
The dragon which helps Chihiro countless times.

Zack Fair, Final Fantasy VII
The soldier who was always chasing his dreams of becoming a hero.

Nana, Elfen Lied
The diclonus who just won't kill.

Nate River a.k.a. Near, Death Note
The apprentice of L.
