I like the fireplace, including the stone hearth. Clean it up, add a mantel and use it for g'ness sake. I don't know where you live but we find ourselves dependent for heat from our wood stove now and then.

A "chunky" hearth such as the one you have is a trip hazard. I would replace it with one that is flush to the floor.

What is your decor? Modern, transitional, traditional? For Modern or Transitional, you can paint the stone white for an updated look. Depending on your decorating courage, in a modern decor, you can paint the stone a wild color such as yellow, orange, lime green or purple - whatever matches your color scheme. For another very modern look, you can cover the stone with durrock and then affix mirrors to the entire face.

For a Southwestern or French Country look, cover the stone with Durrock then plaster the surface with a rough mixture of several related colors of sanded grout. Use mediterranean patterned tiles for the hearth. And, be sure to add a mantel made of a semi rough beam stained to match your flooring. Bracketsandbeams.com has an excellent assortment of realistic faux beams that are fireproof.

If you have traditional decor, that will be more of a challenge because the fireplace surround is not symmetrical. If you can remove the right side where the woodbox is located, that would give you a more traditional looking fireplace. In that case, I would remove ALL the stone and replace it with a painted wooden surround. You will need to have a non-combustible material from 6" to 12" around the firebox. Check with your local building codes.

Certainly clean the stone. You should also have the fireplace checked out to ensure that it is drawing properly. Because of the smoke stains it may have a blocked flue or other problems. On the other hand, the previous owners may not have known how to build a fire.

I like it also. For me, I'd just clean it and add a really nice mantel. I might also change the interior of the firewood cavity since it's brick and doesn't match the exterior of the fireplace.

I don't think it's an issue being non-symmetrical. My parents had a traditional home, except it was brick, with the exact same configuration.

If you do paint it stick to neutral colors found in nature, or white. I think you'll regret anything else faster than you think. I also think once you take down the wall paneling and change your floor color you might find the fireplace doesn't bother you quite as much as it does now since it won't be "fighting" for attention any longer.

Of course have it checked. Most likely the smokey appearance is due to someone building too large a fire (too often) and the smoke climbing out of the firebox but it also could be for other reasons as mentioned. You can always have a metal strip installed along the top part of the box, to help keep the smoke inside BTW. Not expensive at all.

Post pix when and if you ever get around to changing this.