The iPad is gonna crush the Kindle? Well that's what the folks over at All Things D think.
However, the article is an oversimplification. Kindle books can be read on the iPad as well as on the Kindle. So the one device is outselling the other device is a very narrow view. My guess would be that Amazon is selling more Kindles not less because of the iPad. Plus, the Kindle for iPad is the best book reader available on the iPad. More books, better interface, you name it.
Without eBook sales included in the analysis, you are not getting the whole picture.