How do you feel about wall art? I have conflicted feelings about decorative stuff on walls. It's so easy to get sick of posters, even if they're neatly framed. Paintings, a.k.a. Fine Art Capital F Capital A, are good in theory, but expensive in execution. Maybe floating wall shelves are the answer. You know, little decorative ones that you put knick-knacks on? You can rotate the knick-knacks when you get tired of looking at them. Make your own little wall art gallery. The shelves have function, so they're sort of justifiable for minimalists. I like these ones shaped like wood from West Elm, on sale for 2 for $69.
You could probably saw these wood slices in half and turn them into shelves. Each are about a foot across. But they cost $29 a piece, also West Elm. Is that bad? Is that good? I don't know. If you happen to have a tree lying around and can slice it up yourself, that's a better route.