..as to offer my opinion.

Since you asked, and only since you asked, I 
think you should sell her.

I don't collect Slayers so I'm not interested in 
it (though it certainly is gorgeous!), but I 
remember the last time a cel like that one 
became available there were a ton of people who 
nearly fell all over themselves trying to get 
it.  I mean if you really really love it, keep 
it sure. It's not like you have a duty to sell 
it or anything.  But I think if there's any part 
of you thats thinking about selling it.. it 
would be a nice thing to do so that some of 
these truly rabid slayers fans could have a 
chance at it.

Just my 2 cents.

-aethel