I believe there are some worthwhile comments here about "just return it".
That said - I purchased a new 15" MBP a few days ago and returned it today. The speakers were the worst I ever heard in a Mac. The Toshiba drive was noisy and created an oscillating hum that was unacceptable.
I paid a bit more and now have the 17" MBP - dead quiet and excellent speakers.
Issue resolved.
mine in my sig makes this fan noise even at idle .. brought it to the apple store earlier today and they said its normal .. but its quite annoying .. 17 is just too big for me to switch to tho