I've written a new article called "The New 2010 iMac's and Poor Quality Control" I posted it here as there are some points that we got from this forum too especially about the buzzing
http://www.techulous.com/news/the-new-2010-imacs-and-poor-quality-control.html
http://www.techulous.com/news/the-new-2010-imacs-and-poor-quality-control.html