Im kind of the same opinion as stated above.  
There are soooo many cels in a series that 
there's at least 100 or so shots that could be 
considered the best of x character.  

However...

This cel I have I can actually say is one of the 
best depitcions of this character in the series.  
I know I show this cel alot, but for this post I 
felt it best met the example.  There are a ton of 
cels of this guy that I would kill for, but this 
particular one is just perfect.  It's like a 
photo snapshot!  I can never say how much I adore 
this image ^____^  And, while there are other 
shots that I think are just as, or even more 
awesome than this one, I have to say this is one 
of the best scenes/shots in the series.