One of the things I havent heard discussed which I think gives the Celtics the upper hand is the fact that the Celtics will have had to defeat arguably the best four players in the NBA to win the Championship (Wade, Lebron, Howard, Kobe).
I think having to have game-planned for all of these different types of great players has allowed the Celtics to learn not only how to defend these different positions, but also how to defend the best in the business.
In retrospect, the Lakers havent really played anyone that tough in the playoffs. The Celtics will have four guys on the court at all times who are dangerous to go off at any moment. The Lakers havent seen a team like that in the playoffs yet.
So I think through the talent faced already, the Celtics have the upper hand, and thats why I pick the Celts in 6. Celts will win Games 1, 3, 5, and 6, and Win Banner #18. At least thats what I hope.
In any event, go Celtics.