I would love to have a cel of any of the Eva's 
from Evangelion.  I have only seen a couple and 
they are out of my price range.  These 2 aren't 
anime, but I would like to have cels from The 
Simpsons and Batman Beyond, both are also very 
pricey for my checkbook.  The one from The 
Simpsons I really, really want is where Bart just 
bought the animation cel from the Itchy and 
Scratchy show, and he paid $350.00 for it, and 
all it is is a cel of an arm.  It was packaged in 
a tube that said "animation cel, do not roll".  I 
just love that scene, it cracks me up everytime, 
even more so now that I collect cels.

Sorry, I know you said "one show", but I just 
couldn't pick one!