Like Ciaran said, It depends on what it is, and, more generally, if 
it is OVA or TV.  There were a lot of cels to the TV, and the 
market was flooded pretty early.  Compared to the OVA, the 
market quickly stabilized at a relatively low price.  That doesn't 
mean that there aren't certain key scenes or characters that 
people still suffer greatly for, but there are certainly a high 
number of great looking, but similar, cels out there that can be 
had at a bargain.  

Now, the OVA is a different story.  Any cel was difficult to get at 
a reasonable price (relative to the quality) not so long ago.  
However, once the Japanese collectors started following the 
market over here, they started coming out.  You can now get "B" 
and "C" grade cels at reasonable prices, but the high end are just 
as difficult to get as ever, and demand just as much.  The top 
end cels can still run over $1K, and most "A" grade run >$400.  
If you have any quality OVA cels in your collection, feel free to 
contact me.  Odds are I'll at least be interested if they are 
significantly different from what I already have. 

In case you couldn't tell from the posts, there are still many of 
us who maintain a high level of interest, and probable will for 
some time.  ^_^  

Robert