Ohhhh, this is a tough one but I choose Star Trek. Sure both series have gone down the hill (Star Trek with its series ... Voyager and Enterprise which in my opinion are not as great as TOS, TNG and DS9) and the last three movies (Phantom Menance was good but after that, they weren't so great.)
Star Trek might not be directed by George Lucas but it is a great series and it does have some good movies (not counting Nemesis.)
Magic: The Gathering or Yu-Gi-Oh?