Shorter mantel and much closer to the FP surround IMO.

This one below is even mounted lower

Staining the wood a dark color, but a touch lighter than your floors should complement both the floor and walls.

I like the longer one but definitely agree the mantel should be much lower (closer to the actual fireplace).

Wood-colored but not as dark as the floor.

Shorter sized mantle composed of a similar material or similar color as the fireplace tile surround. The fireplace has a beautiful classic look. I think it deserves something classier than a wood stained mantle.