Whether it be your child's initial or a short word, typography in kids' rooms is a trend we're on board with. We're especially fans of mix-n-match letters which is good since these brightly-colored enamel letters from Urban Outfitters are (inexplicably) only available in 16 letters.
About 10" high, we like the three dimensionality (we checked - that's a bonafide word!) provided by their 1" thickness (but hollow so they aren't heavy to hang). Each letter is $14. If you can't find them in store, they're online here.