I'm very new to this whole concept of cel 
collecting, and maybe that's why I still love it 
so much. I learned long ago with comic book 
collecting that you're not really like to make a 
retirement investiment egg unless you really luck 
out, and you should only get INTO the hobby if 
you love the object of your collection in and of 
itself. Come talk to me again in six months, and 
it is entirely possible my tune has changed, but 
I'd say that if you have cels you love, KEEP 
THEM.  The way animation is going, they can only 
appriciate in value to the outside world, and 
hopefully they're already priceless to you.  If 
you've found another hobby that has your 
attention, then spend your money there, not in 
new cels.  But I don't see why you can't start up 
a new collection while out having to totally give 
up your old love.

But this might bring us back to my newbieness. :)

Best of luck however you wind up jumping!