Either the color of the mantel or a shade lighter than the wall color. This is one brick that is screaming for paint.

Agreed! Thank you for your input. I was thinking a lighter khaki color. Someone suggested black or dark charcoal- any thoughts on that?

Same white as the mantel and surround. A couple flat seat cushions in colors would be good additions if you need extra seating.

It has been over 10 yrs since I painted my fireplace brick the 1st time. My husband also removed the old and ugly oversized dark wood mantel and installed a mantel and wood surround very similar to yours. Over the years I have tried a few different paint colors and painting techniques. For my room and fireplace, the best option has been to make the fireplace blend in rather than draw attention to it. After all of my experiments, I conclude that painting the brick the same color as the wall, the mantel and surround a soft white and having a black screen/metal enclosure gives me the best result. Don't be afraid to try and remember, its just paint.

a medium grey could also work, given your mix of neutrals, but I imagine something in the realm of the wall and mantel is best -- mantel tone will make the ledge show up more than wall tone will, but you'll just have to see which you like. I dont' know why, but I like the idea of a grey that's similar in saturation to the wall, but, you know, gray. :)

A few options shown below:

Is it a wood-burning or gas fireplace? If it's wood-burning (and you use it), a darker color will hide soot, etc.

ITs wood burning and we do use it.

From experience (we have a white painted hearth at our lake house and I have had to repaint to freshen it up from the ash/ soot), darker may be better.

It looks great!

Same color as fireplace or carpet.

In the long term pull out hearth.

And install code compliant gas fixture in firebox.which will allow you to run new flooring to fireplace,which gives a much more balanced and clean look