I have a theory about the Lakers' defense. Their D is indeed one of the league's best - when both of their bigs are allowed to stay inside, protect the paint and block shots. But if a team has a big man that can come outside and torch a D with his jumper, then all of a sudden that upsets the scheme. Troy Murphy did it for the Pacers, and Rasheed Wallace did for Detroit. At that point, a good slasher (see: Iverson, Allen or Granger, Danny) has enough room to get inside and have his way. When this happens, the entire defense struggles and they end up having to try to outshoot the other team.
I'm looking forward to seeing them play against Utah on January 2, assuming the Jazz are healthy. Mehmet Okur can pull a big man out of the paint, and Deron Williams will be able to get whatever he wants. They have the kind of offense that can score on the Lakers - the variable will be whether they can play enough D to win.
As for the Celtics, I think we have both parts of the formula. Not only am I confident in our ability to limit LA's points, but Kevin Garnett has the ability to step out to 18 feet which should let Rondo and Pierce get to the rim at will.