In the interest of full disclosure, I work for IKEA. They have some great textiles and do a lot to ensure the safety of all of their products--especially children's products.
The curtains are also much longer than what you get in most places and you can use the extra fabric to make matching pillows, cover a stool, etc.
Think about picking a pattern for accent and doing a base pallete of solids. You can add lots of throw pillows and big cushions for floor seating. You can easily change up the look without getting locked into a theme.
They also have some great accessories...net canopies, interesting toy storage.
I've used white/off-white base and added color in my drapes, walls, pillows, art...and I can just bleach the heck out of something if it gets dirty.