I'm very close to pulling the trigger on a 2011 21.5" iMac. My only concern is how difficult and costly repairs are with the iMac and the feeling that the refurbished machine might be more prone to hardware failure. My biggest concern in the hard drive. Does anyone know if refurbished iMacs come with a new HDD? And regarding resale value, is it reasonable to expect $500 for it 2 years from now? Thanks!