Wall Decals

www.fathead.com have really good decals. I work at a pediatric urgent care center one night a week and we have them hanging on the wall and they're great!

I am not sure how elaborate you want, but in the past I have found cute ones at the dollar tree and my boys really enjoyed decorating. My youngest removed and replaced a dozen times probably

yes, I got them at babies r us and buy buy baby.

I bought these animal ones for my son's room. I get so many compliments. This site has a lot of great, cheap options:
http://www.walldecorshops.com/WA15224.html

I bought the set of Dora decals from Wal-mart and they have lasted a long time now. I bought two sets and spent about $25 and they have lasted for about a year and a half so far, including a move to a new home. They look cute and last, I highly recommend. Walmart has several different options.