Ergle...it's a tie between three of my Fushigi 
Yuugi cels, but if I had to choose a particular 
one...it's my flashback cel of young Hikou from 
the OAV.  My Miiru pan and Suboshi cels come 
close, but Hikou wins for these reasons:

1.)  It's a flashback cel, and not just any 
flashback cel, a very famous and exceedingly rare 
one.  I've only seen two other cels from similar 
sequences from the OAV, and one of them only had 
Hikou's arm.  (Though it did have young Chichiri.)

2.)  The color tones are very nicely done in 
shades of light tan.

3.)  It's just a gorgeous shot of one of my most 
favorite villains from the show.

4.)  Comes with original sketch, background, 
dougas from other parts of the sequence, and is 
three layers, two of which aren't stuck.  ^_^

So...he wins, but only by a small shot.  ^^;;  
Enjoy him!

-Chaotic Serenity