I don't know if this was already posted or what, but if you are a sorry sap like me and bought the MDD power mac RIGHT before the new MDD power macs were introduced, Apple is willing to give you a price break. I called apple up today hoping that i could exhange or return my MDD power mac (DUAL 867) for the newer DUAL 1.25 and pay the difference or whatever. Unfortunately they wouldn't let me but instead offered me a price break. The person i talked to told me i qualified for a $300 credit. So i graciously took the credit, and even though i couldn't get my mac exchanged, they at least did something to appease those of us who were unlucky enough to buy a MDD power mac right before the new models came out. Now i don't know if the price break is fixed at $300, you will have to ask when you call them.
Also, in order to qualify for the price break you would have to have ordered your power mac AFTER January 18, 2003. (i don't know if the price break applies to other mac models)