Wow, thanks for the great response! Please keep it coming.
I'm surprised by the vast majority of people who said their MBP is dead silent! Is this the case even in a quite room when you're sitting right in front of your MBP? I can definitely hear a low hum/whirr with mine in this situation so I guess mine may be a bit abnormal.
How do you shut down cores? I didn't know you could do that. Does it save much power / extend the battery life?