fireplace question. Is it worth it to remove one?

[Letitia Harris]

Hi all,
I'm looking at a prospect that has a fireplace chimney that's separating from the house.  It has pulled away 2 inches at the top, towards the roof.  It has some issues that'll need repairing, along with the separation issue.  The house has central heat, so I'm considering removing the chimney above the roofline, repairing the roof, and just having it as ornamental inside.  It looks nice inside, but isn't necessary to warm the house.   I've never dealt with a fireplace before.   Thoughts??
Ideas on what this might cost to repair?