To paint or not to paint?

Our living room bookshelves and mantel need some serious help. They're decorated with frames from the photo wall in our old house and random pieces of stuff with no coordination. We're debating painting the shelving but don't want to end-up regretting it one day. We also contemplated painting the brick, but I think we've ruled that out.

Current state:

Option 1 - all white:

Option 2 - white with a dark back:

Option 3 - white with original wood-stained back:

Thoughts?