Today, right now, I probably dislike LeBron more.  Kobe's calmed down and matured a bit, and LeBron is still in his brash, arrogant phase.  Not to mention we're playing LeBron for the next couple weeks.
But taking their careers as a whole, I've disliked Kobe much, much more than I've ever disliked LeBron.  And Kobe is a Laker.  So I'm definitely voting Kobe.