Mine started out with the same symptoms, and over time the noise will begin to get louder. At first I was worried I would have to guess at which wheel it was, but it is now brutally apparent that it is the driver side.
how much does a new wheel bearing cost? i test-drove a 00' Bonne today, and once i hit 2000+rpms or 30+mph, a loud constant noise would come from the front-end of the car... it didn't change in pitch as i revved the engine, so I wasn't sure what it was... the symptoms sound similar to this though!
I wouldn't buy the wheel bearing assembly from Advanced. I bought two bad ones from there. Pay a little more for the good one and you will be much happier with it. You can get a good one from Napa or Carquest. Also, the GM parts online are supposed to be good too.
I bought one from NAPA, and one from Advance...both roughly $100. Within 6 months, each had the wheel speed sensor go, and trip the service stability system code. The bearings themselves were fine. You can try the less expensive hubs, just as long as you know that you might be replacing them again.