As others have suggested, your children's responses are probably your best guide; look for more of what they respond well to. I imagine the best music is light, easy to follow without being either too soporific or too insistent. I think Satie and Smetna has some music like that, in addition to the composers already mentioned.

@ E5150. That's a nice Paganini piece! If you're not too much of a purist, you might enjoy this:-