...the fact that anime cels themselves have 
absolutely no value.  You can't eat them, or wear 
them, so they don't have the basic necessity 
value of bread or fabric, and there's no cost in 
producing them that must be recouped in a sale 
(as with cars, etc) so cels are one of the very 
few items out there that have no value and yet 
command very high prices.  There is no such thing 
as the "value" of a cel.  There is only an amount 
that people are willing to pay for it.  
Collectors generally agree that rarer and more 
popular characters are worth into the hundreds of 
dollars, but that's a completely arbitrary amount 
based solely on supply and demand.  In 50 yrs, 
I'll bet that Deedlit cel isn't worth a whole lot 
like a tiffany lamp or fine art piece would be, 
simply because in 50 yrs a very small percentage 
of the population will even care about what 
Lodoss Wars was, let alone pay big bucks for a 
cel from it (whereas collectors will never tire 
from paying lots of money for art or lamps... 
sorry, I just don't see cels as the "real" art 
pieces a lot of people do.  They're popculture 
art pieces, not fine art)


That said, I think an A-level Nausicaa with 
background from a key scene (the acession, etc) 
would probably be THE most expensive cel you 
could run across.  The question of what's the 
most expensive series isn't quite as interesting 
to me as what that one particular most-sought-
after/expensive cel would be... The Holy Grail, 
if you will ^_^