Digitimes Research analyst James Wang, has high expectations for Amazon's newest Kindle Fire HD tablets. He predicts that sales of both versions of the tablet will cumulatively hit 5 Million sales by the end of the year. Wang expects that the 7-inch version of the Kindle Fire HD will likely sell 2.9 million units, while the more expensive 8.9-inch Fire HD will ship an estimated 2.2 million units. Here's a quote from the source:

Components for the 7-inch model began mass shipping in July. Shipments are expected to reach 500,000 units in September and close to one million units in October. Total shipments in the second half are estimated at 2.9 million units.

The 8.9-inch model will only be produced in small volumes in September, while its monthly shipments in the fourth quarter are expected to reach one million units at most. Total shipments of the 8.9-inch device in the second half are estimated to reach 2.2 million units.

Digitimes Research estimates that the 8.9-inch Kindle Fire HD will be able to achieve total shipments of 3.5-4 million units before the product is phased out of the market.
Considering how quickly the original Kindle Fire sold, it wouldn't be surprising if his numbers were accurate. We shall know in a few short months.

Source: Kindle-FireForum via DigiTimes