While I’m doling out all of this invaluable parenting advice, I thought I should mention that everything I’ve said about movies applies quintuply to music, and especially to music listened to in the car.
More simply put: There is absolutely no reason to subject yourself to so much as a single note of “children’s music.” If you play real music, the little darlings will embrace it as their own.
Possibly this advice has arrived too late for you, and you’re already up to your ears in Fred Penner and Laurie Berkner. Do not despair, for you have a mighty ally on your side who can help you wean your kids away from the dark side.