It is amusing to sit here and read all your posts and theories of what is wrong with the D100 exposures. I have done extensive tests of my own D100 meter. I would invite you all to do the same. We should all know that a camera's meter is supposed to make whatever you are metering off of have an average brightness level. You can see this if you take a photograph of a gray card or any evenly lit object. No matter how bright that object is, it's histogram will have a peak in the middle. Remember, this is only when you photograph evenly lit objects. In my website http://fotogenetic.fade.to I explain how I tested my D100's meter against my Nikon FA's meter by photographing evenly lit walls. Both cameras metered exactly the same! Yet, the peak of the D100's histogram was slightly to the left of the middle. When I used +0.3 EV, the histogram was perfectly in the middle. I did this test on several evenly lit objects using spot metering, matrix metering, and center weighted metering with the same results.
So fellas, it's not the meter! It's the tonal distribution of the image. The D100 is simply assigning slightly darker values to each pixel than it should, despite the exposure being dead on. How do you fix that? Firmware 2.0 does not address this, so don't think that you'll solve the underexposure issue with that. If you use EV settings, you'll lose 0.3 stops of exposure, possibly making your photos more blurry (slightly) and blowing out highlights. So what do you do? You can either just live with it or you can use a custom tone curve to correct the problem.
There's some people out there who think that custom tone curves only work in some situations and not in others. Well, they're right if the custom tone curve does anything more than correct the brightness level to what it should be. If the images from the camera then don't work in some situations, well, of course. There is no one setting with any camera that will know exactly what you are inteding to capture. That is up to the photographer. As long as the camera produces images with the expected brightness level, the photographer can adjust settings to his taste. That part cannot be taken out of the equation. If it is, you will not get perfectly exposed photos no matter what camera you use.
Well, I made a custom tone curve that I've tested with almost 500 or so photos that gives exactly +0.5 EV of compensation. I chose +0.5 because in my eyes, it looks right. I will make a +0.3 one shorthwhile.