I think a lot of the people who are complaining about road noise have little experience with an all terrain tire. I've had my LTZ's since September, and have about 7,000 miles on them. By all reports on this board, they should be making a lot of noise by now.
Yes, they are a little noisier than they were when new. They are also noisier than the Michelins I replaced (which, by accounts on this board, are some of the most quiet tires you can get for the LR4). But they are still relatively quiet for the kind of tire they are.
LR4's come with substantial sound deadening, thicker window glass, etc. If I have my windows up on the highway and stereo at just a normal volume, I'm not sure I can hear the tires at all. Maybe a little. But it's definitely never risen to a level where I'm bothered.