You might be right to do what you're doing, but I think that we have all been fed so much information that we can't make our own minds up anymore and that we are all paranoid . We read that the D3S is a dust magnet, that the D7000 has oil spots, the D800 has left focus issues, and we need focus aids to make sure that our lenses and bodies are in harmony.
Ansel Adams was just lucky that he had a camera that didn't spit oil and his lenses were -0- right out of the box on the FoCal scale.
I'm guilty of these same complaints and may have contributed to your doubts. I just used my Giottis blower to blow some more of the dust out of my D600, and it is now "perfect."
I told my boss (my son) that tomorrow I'm heading out to Lake Michigan with my D600 to get some pictures of the 25 food waves. Maybe I'll take my D3S too, but I haven't checked it for dust spots, ever!
Don't read any more of these threads. There's a lot of nitpicking going on here. The D600 is one of the finest cameras ever made. And sure, there are a couple of lemons, but get your new one and just go out and shoot with it and see if you like the images.