Oversized single initial in kid's room. Could do this in any color and font. This design is from Cari Berg Interior Design & was featured in the November/December 2011 issue of California Home Design. Or last name initial on family room or kitchen wall!
From the excellent Paris-based Minakani Lab, which aptly is going through a name change and will become Bien Fait, "The Wild" - which I suppose is a children's pattern, but could easily work in a grown-up setting.