I think the cels prices are fluctuating (down 
right now) also but I don't think it's because 
DBZ is less popular). Ask yourself this... when 
the prices were insanely high, weren't you seeing 
really nice quality cels out there (on ebay in 
particular)? I remember seeing very nice 
Gogeta's, Majin Vegita's, sealed Trunks/Gohan 
from Trunks special. The reason why the market is 
down right now (I think) is because the quality 
is poor. The good cels though still draw the 
money.... I saw a a Freeza vs. Goku go up to $440 
or so a few weeks ago... because IT WAS A NICE 
CEL :) - When cel prices skyrocket though, it's 
GOOD!! .. at least for me and those of us who 
WANT to buy good quality cel's because that's 
what draws them out of people's archives... cels 
I wouldn't have had a chance at if the seller 
didn't see that DBZ cels are hot right now. So if 
you ask me, keep hoping for skyrocketing prices 
because once that happens, some REALLY NICE cels 
are going to come out from nowhere that you might 
have thought never would have been sold. 
Anyway... my 2 cents.