component cost of an iMac Core Duo: $873

iSupply made an estimation of the total out of the factory" cost of a 17" Core Duo iMac: $873.
The Intel processor costs $265, the Northbridge/Southbridge $45 and the ATI chip $30. Apple's margin is estimated at $300... which is in no way the same as profit!
You then have to substract the costs related to R&D, shipping, advertising etc.