Floor to ceiling wallpaper on all four walls can be way overkill, but by mounting a chair rail and papering above and painting below, you get the best of both worlds: a fun pattern grounded by solid color.
We caught a beautiful example of the idea while watching Emily Henderson on HGTV's Secrets from a Stylist last week. Do you read her blog? You should! She's totally light-hearted, fun, and has an amazingly keen eye for design. She designed this amazing living room, and the wall treatment jumped out of the tv at us because it would work so well in a kid's room. And the guest bedroom she designed in the top photo is a great example of how gender neutral a wall treatment like this can still be.