Hi All Wanted to upgrade my Macbook HD and just wanted your comments or suggestions on the new WD 500GB 5400rpm or the SG Momentus 320GB 7200rpm for Macbook Aluminium. Which one is better? I want something that's no noise, less heat or no heat and no vibration. I heard that the Momentus 320GB produces a lot of vibration and other posted that is quiet. I'm just little confused. any suggestions are greatly appreciated. Thanks in advance.