Hey guys, I am selling off my 160GB Hitachi hard disk that came with my aluminium macbook and i am intending on upgrading to a 320GB hard drive. I am thinking of either: 1. Hitachi 5K500.b hard drive 2. Hitachi 7K320 hard drive 3. WD Scorpio I am leaning towards the Hitachi as I have had no problems with mine, and I love the fact that it is very quiet and does not produce too much heat. Between the 5400rpm and 7200rpm, which should i choose, price diff is negligible? My concern is additional heat, noise and vibration. I was told that battery life sacrifice would at most be 10 minutes? Is this true? If we are looking at 7200rpm, between the Hitachi and WD, which would you choose? I need to decide quick as someone has expressed interest in buying my current hard disk. Cheers.