Just as a note, but not something to recommend unless one has quite a bit of money for equipment, since I purchased a full-frame camera (the D700), I have become spoiled with the quality of the images. I don't know what they are called in other brand names, but with Nikon, DX cameras have a smaller area with the sensor, thus, one doesn't get quite as much "territory" in the image as the full-frame FX cameras do. I can tell quite a bit of difference between my FX and the DX (D300) bodies.
In a sense, I made a mistake in wanting a Nikkor 70-200mm f/2.8 lens. When I got it, all I had was the D300 (DX) and didn't know the difference. Later, when helping a coworker's wife choose a camera, I found out that the 70-200mm lens was an FX lens. Well, of course, that led me to looking at FX cameras. I got my D700 on E-bay for about $1500 for the body alone. When it sold new, they were around $3300. While I do have one issue with the FX, it is still the camera I prefer to use, and do use the most.
Terry,
I have a D5100 and recently bought the exact same lens as you ($$$ ouch) however, have found that although I will purchase a full frame camera in the future, the 2.8 lens works just fine on my body.