I would go with neutral beige/tan.

I would do white, the same colour as your closet doors. With your beautiful quilts and green carpet, I think white would provide a nice cottage-y feel and open up the space a lot. Paint all your dark brown shelves white at the same time!

Another idea is super light grey. Grey and espresso look great together and your quilt will really pop against it.

I love that colour Sophie and I agree that it looks fantastic with the bedding, but the OP's carpet looks to be a pine green or possibly almost teal. Would they clash?

Sophie - thank you. I really do love color and tan just feels so... blah. Also, I'm not too concerned about the carpet, the next project is to replace it with vinyl plank flooring.

The green Sophie suggested would look great with vinyl plank floors. Are you going to add a headboard? I'd consider new curtains as well or better yet, wood roman shades.

kateinparadise - I'd really like a headboard but I have a sleep number bed and foundation; the foundation is plastic so I don't know if a traditional headboard would work with it. I agree with getting new curtains (and definitely an appropriately sized curtain rod).

Megan, you could always do a wall mounted headboard to avoid having to attach anything to the bed frame itself.

I think a nice tan color like this would compliment your quilt.