I'm a big fan of the History Channel's series The Universe and National Geographic Channel's other series Naked Science. Their thought-provoking episodes always manage to spark my imagination with "what if" scenarios.
A Traveler's Guide to the Planets delves into what we know about the planetary bodies in our solar system and speculates on all the mysteries that are still unsolved. From the "hot zone" planets of Mercury and Venus, to Earth's neighbor Mars, to the giant Jupiter and the beautiful ringed Saturn, to the ice giants of Uranus and Neptune, (and an episode on the demoted Pluto), it is chockful of facts and amazing visuals, all presented in a totally entertaining way.
I wish the major broadcast networks would invest in television series like these and expose a broader audience to this kind of stuff. Until then, the cable/satellite channels are a haven for TV viewers looking for stories about our universe.