Scrubbing the stone with, of all things, bathroom cleaner will get the soot off of it, so you can really see what you have. With the gray mortar, it might look really nice as a bridge between your carpet and gray walls just as it is. Too bad you can't keep the flooring.

Why are you putting in carpeting when you have a hardwood floor? Why not have it refinished? It will enhance the look and value of your home much more than covering it with carpeting.

Instead of gray, I'd go with a warm tan or grayish green for the walls. It will look much better with the woodwork.

Have the stone cleaned before you decide to do anything else. It will bring it back to life. It's very pretty, just needs some TLC. You can see the smoke stains in the front there. Once those are gone, it will look much better. Also find a nice screen to go in front of it. You might the stone mantle framed out in a reclaimed wood too.

If the home inspection did not include it already, have the chimney inspected before spending any money redoing it. The soot stains indicate a problem that needs to be corrected. If you don't care for the fireplace stone, it can be replaced with something new.

I love the wood floors! I don't think the wood trim or the stone will go with the gray carpet. You might consider using trisodium phosphate (TSP) to clean it, you can get it at the hardware store. Here are some links with different ideas.

Similar fireplace painted one color (scroll down): http://www.apartmenttherapy.com/heathers-comfortably-glamorous-121051

Whitewashing: http://aheapeoflove.com/2013/09/white-washing-an-easy-tutorial/

Faux painted: http://handpaintedmuralsfauxfinishwalls.blogspot.com/2007/08/example-of-faux-finishing-when-faux-is.html

First, if the floors are in decent shape, I would encourage you not to install carpeting. I'd rather see you leave at least the perimeter of the floor exposed and add an area rug. Try cleaning up the stone but if you really hate it, paint it. I have had several clients paint stone and/or brick fireplaces with great results. Good Luck and Happy Decorating!

What is your decorating style preference? It's far easier to change the fireplace surround once you've determined what is your style! If you're on a budget and/or like the bricks as they are for the time being, after thoroughly cleaning all of the soot away, I'd try thinning down a paint color of your choice and doing a wash over it.

The brick hearth is painted and needs attention. The stone on the fireplace and mantel can be stained a darker color.

You may attempt to tile over the existing or hire a handyman/tile person to install a nice stone tile. It is a one day job and should not be too costly.

Refinishing the wood floors is not expensive and a great alternative to carpeting.

Best wishes.