I have a MBP 13" i5 with a 320GB HDD which come standard with the baseline 13". I recently noticed that on the bottom right area or to the right of the trackpad that I can hear and feel a humming noise and vibration. I'm not sure but i swear when I first got it like a week ago I did not hear this. Is this normal? I know that the disk is spinning but when I went to the apple store and felt the same model with the same HDD I didn't feel ****. :$