Wall color???

Lindsey • Mommy to 3!
My almost 2 year old son will eventually be room sharing with the little girl I am pregnant with now. What is a good neutral wall color that they wont outgrow in a year or two. Our walls are currently this drab beige color and I want some color in the house. Their nursery furniture is a dark cherry color. I was thinking about maybe a baby blue color with pink, yellow, and purple decor on her side and navy blue, green, and yellow decor on his side...but idk... I have such a hard time visualizing...