Entry-level DSLR models are very interesting for manufacturers. They can reach high volumes, 
there is a much greater group who can afford these cameras and you can bind new users to your own system. There’s a reason why the competition in this segment is so fierce. Nikon’s newest weapon is the D40, and Nikon is using it to raise the stakes. The Nikon D40 is primarily meant for consumers who want more than a compact camera. In the profile of the target group, Nikon sees a family person between 30 and 70 years old. The typical user of the D40 is looking for a camera that stimulates creative qualities and reacts quicker than a compact camera.
Nikon D40 - 6 Megapixel digital SLR camera
Remarkably, the Nikon D40 has not joined in the Megapixel race. Instead of 10, this camera ‘only’ has 6 million pixels. The number of Megapixels has a large psychological effect on the average consumer. This can be explained in part by the early years wherein the number of pixels contributed to the quality, but it was mainly the manufacturers who spurred each other on to the 10 Megapixel limit in such a short period of time. It looks as if this record will shortly be broken with the introduction of a 12 Megapixel sensor by Sharp that will be used for a compact camera. Do we really need ever increasing amounts of pixels? The answer, to be blunt, is no; we need better pixel quality and you can get high quality prints sized an A4 or even A3 with 6 million pixels. With the introduction of the D40, Nikon as a manufacturer is making it clear that they share this opinion; 6 Megapixels gives the photographer top quality. Nikon D40 Digital Camera Review