It's a wonderful blank slate to work with! You could have worse problems;) I'd avoid doing the same thing on both front and back. I'd start with an anchor piece on each side and work around that. Maybe a meaningful piece of artwork, large photo canvas, even a beautiful wreath for one side. Maybe a mirror on the other side. They would have to be large enough to take up a fair portion of your wall. I love the look of multiple photos stacked against each other (one big in the middle) but each in different heights and frames for lots of good height and depth variation. You could also have fun on one side, maybe your sitting room as conversation pieces - a large framed map of a country you may have visited with vintage travel books stacked on one side and a compass and globe. Whatever you pick, have fun! Looking forward to seeing photos once you complete it!

Rebeccamom123..LOVE the idea of a mirror. Maybe leaning it on the mantle. We have tried to hang something on the "wall" of the fireplace but the grout was soft almost and I don't trust anything hanging from it but the thought of a bug mirror on one side I love. My children were in my brothers wedding last year and I am thinking a big picture of them on the other side. Thanks for your input:)

Here is an example dressed up for Christmas that reminds me of your space. Even without the holiday stuff, the leaning mirror and lantern would look great on your mantel!

[Contemporary Living Room[(https://www.houzz.com/photos/contemporary-living-room-ideas-phbr1-bp~t_718~s_2103) by Tacoma Interior Designers & Decorators It's The Little Things...

Perhaps you could hang the mirror from the ceiling - there probably is a joist where the ceiling hits the chimney hits the ceiling so that you could hang it with wire or chain as is done with a picture rail. Being from earthquake territory, a large heavy object such as a mirror on a mantle just leaned against the wall seems precarious.

rwhirley, I recommend these for no-damage to brick -- http://brickclip.com. I have used them for years on my brick fireplace to hold mirrors. Each holds up to 25 pounds, so a large mirror or picture would need more than one, I expect. The link has a video to show how they work. They are terrific. =)

What about the mantels themselves? Should you try to stay in the same color family with both sides? I have just made my single fireplace into a see-through double sided fireplace. One side faces den and the other side faces a sunroom/sitting room. I have existing mantel that is a medium brown but wanted a lighter almost white-washed wood for the other side. A decorator said I should try to stick to same color family in wood but could have different styles of mantels. One is more formal and the other side more rough hewn. The fireplace is mountain stone.