Every tv show (save one that is exceptionally brilliant) has some regular characters who are stronger, and some who are weak. I'm talking about personality, screen presence, and likability. So pick a tv show or two or five and tell me who you thought the strongest regular or recurring character, and who you thought was the weakest.
Star Trek: The Next Generation
Strongest: With Sir Patrick Stewart in the lead, it's pretty obvious who your strongest character's going to be. But I also think Data and Worf were strong, interesting characters. If an episode was Data or Worf-centric you knew it was going to be fascinating and thought-provoking.
Weakest: Again, this one's a shoe-in. Everybody hated Wesley Crusher. Honestly, I didn't mind him that much, but he is quite a weak character. The only episode I really liked that featured him prominently was the one where his teammate at the Academy is killed in an accident. But that episode doesn't shine because of Wesley; it shines because of Picard. Patrick Stewart is possibly the only person who can deliver a full-blown sermon on a sci-fi show and not seem totally disingenuous and irritating while doing it. XD
I also think Troi deserves an honorable mention for being a weak, irritating character.
I have more, but I don't want to tl;dr you guys. What comes to mind for you guys?