TOS: Kirk (Hated him at the beginning but he grows on me)
TNG: Jean-Luc piccars. Lets face it, he is the reason you see the show.
DS9: Either Bashier or Ducat. its a shame what they did to Ducat. If he would continue being the Bad guy turning good, i would be my favorite by far. But he turned generic crazy and evil. shame.
VOY: Hmm this is a hard one. I disslike so many in the show... No wait, its not hard at all. Doctor. Without a doubt. Everytime he is in frame i smile. Sure seven of nine is nice, but they concentrate too much on her, like they order you to like her.
ENT: Havent actually seen Enterprise yet. Getting there though