I do not hear any humming noise (low freq sound like "hmmmm") when I put my ears on the new 2009 iMac but on my model (2008 imac 3.06 8800GS 500GB HD 4GB RAM), I do get a humming noise when I put my ears right beside the screen. Anyone experience this as well? It is not due to brightness as far as I can tell. You do not hear the sound unless you are like less than a few inches away from the screen but it makes an audible "hmmmm" sound. Should i bring it to an apple store????