Elizabeth -- do you like the look of a porcupine mirror? You could scale up the size of the mirror you have...let me find a photo...

Lots more:

http://www.houzz.com/photos/query/porcupine-mirror/nqrwns

Clear the smaller items, get a few bags of bamboo skewers, a couple of paint colors, and boom! Oh, and maybe think about painting brick and mantel all one white/black/color.

I agree the mirror should be larger. If you do that, you might just place some tall-ish candleholders at each end...not much else. Mantels are best when simple, as in Barnhart Gallery's examples. Save family photos for bookshelves or smaller tables.

Elizabeth, I'll be a contrarian. I think your mantel is too high relative to your ceiling height to go w/ larger round mirror, porcupine or not. If you want a mirror to make room appear larger I'd go w/ rectangular mirror oriented "landscape" w/ a frame to match your decor style. I personally am not huge fan of mirrors on overmantel. I'd go w/ painting or print that reflects your tastes.

I'm with Bruce. A lovely painting or print would be my go-to choice (rectangular in shape).

This is my overmantel. It's in DR, not LR, & my mantel is not as high as is yours. The painting is of home where my late mother & her late brother spent their summers after their father was killed during a robbery in '33, so it's a piece of my family history. That's my variation of what I meant by something that reflects your tastes.

Others may think I'm nuts (my wife might agree), but I treat fire & hearth differently than other wall areas. It's not only a focal point, but also more symbolic, fire/warmth, hearth/heart.

I would move the family photos because a person can't get close enough to properly view them, plus the frames aren't great with the brick. I think mantles are hard to do, also! I'd like to see something large, warm, personal or very interesting.

If you're in a tight budget, at least paint the photo frames to match the mirror (which is too small), or find more wall pieces similar to your mirror, but different textures, and paint those to match. Or be cheesy and trendy, (why not?

Thank you everyone for your comments! We have decided to look for a larger rectangular mirror and I am currently on the hunt for some tall vases to use as anchors on the two ends.