Well, I spent about an hour lubing up the brakes on the side that seemed to be making the noise, and the noise seemed to stop for a while. However, after driving for an hour or so, the noise is back just as before. I did notice, though, that my pads are pretty worn (down to the little brake wear sensor), so I will probably go ahead and order Lexus brake pads. However, I am doubtful that this is the cause of the noise.
Does anyone have any ideas on what I should check? I have replaced all of the following recently:
--upper strut mounts
--front strut rods
--front sway bar bushings
Please help!