I am a huge fan of a couple of brands. Elta MD - we get the "clear" not tinted one, it is zinc oxide based. Not too white, and excellent protection.
Also, Colorscience has an amazing powdered sunscreen in a container with a brush that is mineral based. It is so good for kids faces, instead of rubbing goopy sunscreen on your kids face you can quickly powder it on. It's not cheap, but one container lasts a long time. Its not amazing in the water we've found. You used to be able to buy powder refills for the container, but I am not seeing that you can anymore.