I have decided I love wall stickers / wall decals. These are a great way to dress up a room without long-term commitment, which is great for a couple who's reluctant to hammer into the walls and a house that's pretty old anyway.
This was a test run on a small patch of the wall next to the bed. (And yes, we have a white board in our bedroom.)
The long curly stickers were a bit tricky to manage, but nothing impossible with an extra pair of hands. Plus, they weathered a few "oops, not like that" just fine.
My only complaint, now, is all the [affordable] wall decals don't have actual fine-art photography, but leans towards impressive patterns, quotes, and more of the cartoon-like pictures as above. I'd love to be able to hang a landscape or some kind of panoramic image and have always been reluctant because that meant nails--but I can't find a wall sticker equivalent, boo.