I wonder if some perspective might not be in order here. I have a 7-year old D70S with over 30,000 exposures on it. It has had numerous lens changes depending on who's using it. I used an 18-200 mm lens on it for general work, and a 150-500 mm for wildlife, in probably about 70% to 30% ratio. In all that time it's had only one sensor cleaning when it went in to Nikon for repairs. For the rest it has had the occasional rocket blower treatment. The sensor is still free of specs. My son has been using it for two years with 18-55 mm and 55-200 mm lenses, and no dirt on the sensor.
The two-year old D90 that replaced the D70S still has a clean sensor (used with the same lens combination). I don't think I ever had to blow dust out of the D90 - the sensor vibration cleaning system seems to work well.
My new D7000 has done about 800 shots, and so far the sensor is clean.
So when a new camera shows so many specks so soon, there must be something wrong. Where to look for the problem? It could be due to a lens problem (poorly sealed thus sucking in a lot of dirt and depositing it on the sensor), a lens change technique problem (point the camera downwards when changing lenses, keeping camera shut off - an energized sensor is apparently more magnetic than a dead one, and changing lenses in a calm, wind and dust-free atmosphere) or either sticky dirt generated by the camera body or a faulty sensor cleaning (vibration) system. Unless a production issue is found at Nikon, the only way to isolate the problem is through a process of elimination.