I agree with what a couple of collectors said 
above. You can't define a cel to be the best out 
of the whole series. Especially, you are the 
owner of that cel. 

Now, you may probably pick out a cel of your 
favorite character out of a short sequence, and 
define it to be best shot of that character in 
the sequence. Even in that case, it's still your 
opinion. 

I don't think you mean the way that it turned 
out, which is, yours is the best and the rest are 
not. So, here is my contribution to the thread. 
It's a great close up shot of Kenshin. I consider 
it to be a great shot, but definitely not the 
best!