Perhaps a mantle?

It would have to be customized due to the curvature, if at all possible

Maybe dark wood mantle and top of hearth in the same dark wood?

I would differentiate the fireplace from the surrounding wall. If you're painting the wall gray, I would paint the entire fireplace surround a darker shade of the same gray.

Oh gosh yes! Ha
It will be dark wood floors. I just bought this place and was thinking paint before floors

I think your fireplace is completely unique and awesome! Not outdated at all. A fresh coat of paint will make a big difference.

wow what a statement! I see where you got the grey idea from... lots of great pics in your idea books! I think that could really work. Maybe finding someone to do a custom mantle would be something to look into? A beautiful mid tone wood could be perfect....

I forgot to mention... In your inspiration pics the fireplaces are smaller then yours so remember painting all the way up with a grey color could darken the room quite a bit! so probably want to keep the rest of the area fairly light!

I think it DOES need a mantle--something to break up the height a bit. If it were mine, I'd do a mantle out of some kind of metal that could be shaped to fit the curve, then add a tapestry of some sort on a curved rod above it to add interest.

I would not put a mantle.. maybe a stainless fireplace surround that is a little bit broad, and a stainless ledge to 'base' it. A contrasting paint color for the entire fireplace (from the rest of the room).. and then maybe 3 'soaring' art pieces - located at 3 heights across..eg., 3 flowers in different bloom stages? or 3 birds going up? whatever u like....