As I've established (and reiterated), I like stuff on my walls...Not too much stuff, but at least some stuff :)
As I have slowly been decorating Lilly's room, one of the things that I have had some trouble with is deciding what kind of stuff should go on her walls. I painted stripes behind her bed (which I still LOVE and would highly recommend to anyone considering it) mostly because I didn't want to hang anything over her bed. I know I'm weird, but I probably wouldn't sleep at night if there were something hanging over her precious head (literally :).
On another one of Lilly's walls, I decided to use framed fabric as art. I filled Ikea (don't you love that place) frames with fabric that I have used throughout her room. It was a cheap ($15 frame + fabric remnants) and super easy (maybe 5 minutes each) craft project and I think it turned out pretty well.
Also, here are some good looking examples of framed fabric that I found on Pinterest. Obviously these people take much, much better pictures than I do!



http://www.chiccheapnursery.com/2011/real-rooms/fun-fresh-and-makes-me-blush-real-nursery-spotlight/
Let me know if you give this a try!