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

On the run
Killua spends a lot of time running over the course of the series and the OVA, so there are lots of "Killua running" cels. I picked this one because I like the way his hair is drawn and his costume.
 
Added: 3/21/09
 
On the run