If you are decorating your child's room with a Harry Potter theme, have you given consideration to the floor? You can always go with carpet, but if you want to make the room look even more like it came from the Harry Potter series, consider including the floor in your decorating efforts.
The picture below provides you with an idea about how you can include the floor when decorating. I'll be honest, I don't think the picture is meant to invoke thoughts of Harry Potter, but their choice of colors screamed "Gryffindor!" to me. As in the picture, consider adding tile in the colors of whichever Hogwarts house your child likes best.
What you see here are Gryffindor colored floor tiles. You can replicate this look by using burgundy and yellow tiles for a Gryffindor room. Whatever you do, be sure to have fun with the colors.