Birdy

Cowboy Bebop

Dragonball

Flame of Recca

Gundam Wing

Hunter x Hunter

Inuyasha

Mononoke Hime

Oddments

Outlaw Star

Ranma 1/2

Rurouni Kenshin

Trigun

Yuu Yuu Hakusho

Happy girl
Most characters in Inuyasha are angst-ridden at least part of the time, but Rin is admirably (obliviously?) cheerful. I guess coming back from the dead will do that for you.
 
Added: 6/3/06 From: Celga
 
Happy girl