As far as I am aware the widely reported 'whining' issue with the MBP is related to a noise coming from the CPU (Core Duo Chips), rather than the HD.
Specifically, as far as I understand it....The whining noise relates to the CPU being sat in idle mode and hence generating this sound - Work arounds have been generated, such as
Quiet MBP which takes up around 1-2% of the CPU, in order to keep the chips out of idle mode.
The problem is specific to Intel Core Duo 1 CPUs, I have no idea on whether it is still an issue with the 2nd revision chips, but I haven't heard anything on that yet.
Finally, as far as I am aware all MBPs ship with this 'defect', but many people report different levels of the sound on their machines.....One would assume this is all dependent on 1) Each individual's hearing 2) The exact build of each computer.
All of the above is the issue as I understand it and I may well be incorrect in some areas, but having exchanged 2 MBPs myself due to this problem I've looked into it quite a lot and the machine I have now, although it makes a VERY small 'whine' whilst charging.....is very, very quiet.
Good luck with sorting out this issue!