How old is your son and what are his interests?

Well he definitely needs a lamp shade and maybe some large posters for the walls that he picks out.

While I can see you having say on the window shade (that one needs work), wall art at his age is best left in his hands towards his interests. They may not be posters you'd have chosen, but he's getting to the age where he needs to flex some design independence. Work with him at Michael's or art.com as the poster above noted.

Teach him to put the violin and bow away! You never know what can happen if you set it down, even just for mom to take a picture!

I think it needs curtain panels.

Another option for the wall is vinyl...you can get a custom one or just a generic hockey player.