I'll buy just sketches, they are that valuable to 
me. I prefer to have the sketch WITH the cel, 
but will not turn down a cel that doesnt have it 
obviously. I display them sidebyside usually in 
my celbook.
since I was working on tv animation this past 
summer doing alot of the rough sketches, 
actually OWNING the rough sketches for 
animated series that I like, is REALLY REALLY 
cool to me. I feel like I can relate! also, often 
the rough genga (douga? I forget right now I'm 
tired....) the roughs are sometimes more 
personality-full than the final cel, since the 
final cel has been retraced a few times...  

case in point,... I have this cool cel of Filia and 
Gourry with a background. I ordered it just 
cuase they looked nice in the cel (well that and 
Filia has swirly eyes).
point is though, I didnt know it had a 
layout/rough sketch with it. imagine my 

UTTER COMPLETE JOY

when I open the package and there's a 
gorgeous absolutely smolderingly beautifull 
rough sketch in the back. ;) dude, gourry looks 
SO sexy in it.

yes, I am quite mental. :P