Many of the NOVA episodes are going to go above the heads of kids, but they are still interesting and my daughter will sit and watch parts of episodes with me. Unlike Mythbusters, she usually decides to do something else after 20 or 30 minutes.
I've recently started DVRing The Universe on the History Channel. I like this show, but it could be much better. The show does an excellent job interviewing astronomers and making the science very interesting, but their animations and digital effects go overboard and introduce bad science. For example, the other day I watched an episode on comets. The astronomers interviewed explained that comets can originate in the Kuiper Belt or the Oort Cloud. Perfect science on their part. The producers of the show, however, then proceeded to show regions of space filled with asteroids and comets. Filled so much that the fake ship they pretended to be in looked like it was going to be constantly bombarded by these objects.
In a previous post on the asteroid belt I discussed how the asteroid belt, and other regions in space such as the Kuiper Belt and Oort cloud, are not densely packed with comets and asteroids. There are still millions of miles on average between any two objects. The animations in this episode of The Universe implied the opposite. It's too bad The Universe producers feel they need to add these incorrect special effects. The show is just as good, and actually better, without them.
If you have any other suggestions for quality science TV shows, let me know!