The most I ever spent on a cel was $282, for a 
very nice close-up shot of Priss (of BGC fame).  
It also happened to be my very first cel!  Since 
none of my other cels came even CLOSE to being 
that expensive, I've sometimes wondered if it was 
worth the money for the cel, but that thought is 
quickly replaced by "Of course it's worth it!  
It's a beautiful cel!  I've hardly ever seen 
another BGC cel that's this good!"

As for your question of whether or not you should 
spend $1000 on a cel, well...that DOES seem a bit 
expensive for "just" a cel, but if it's your 
dream cel, then by all means, go for it.  Me, 
OTOH, I could think of other things to do with 
that grand, but...I'm not you! =D