Okay, okay - I changed my mind again. I took a new and different approach that will probably make nobody happy but here goes. Consider this a beta test with updates most likely to follow. For now I am not going to promote these presets anywhere but on this post. They are far far far from perfect as I explained here. There are too many variables to make a one size fits all set of presets and to make them perfect they are too hard and complicated to use - hence why bother with a preset in the first place.
Here is what I decided on for this beta - Closely match the contrast/gamma of the Nikon Picture Controls AND add just a couple of color adjustments that are designed to give the overall impression of Nikon color rather than match each and every hue in every lighting condition. To that end the color adjustments I chose to deal with are rather asymmetric - some picture are different than others in terms of what color adjustments they are designed to deal with. Specifically Landscape and Vivid do things that may cause issues on images that really are not appropriate for Landscape and Vivid while Neutral, Portrait, and standard omit the potentially problematic adjustments.
If you are curious - all of the presets manipulate blues to a certain extent over a fairly broad range. This is one of the most noticeable differences in Nikon color vs. Aperture 3 color. Instead of matching hue, saturation, and luminance exactly as NX2 does I went with an approach that will hopefully be a reasonable balance across all images as opposed to matching the blues exactly and causing hideous split color problems in certain conditions. I took the safe way out. The Landscape and Vivid presets also deal with another nagging Aperture 3 problem with Nikon NEF files. The Yellow/Green merge. In a lot of circumstances this is virtually impossible to deal with a one size fits all preset. Again I took the safe way out. There is a certain hue that I consider the tipping point after looking at 1000's of images. That is the hue that I decided to manipulate independently of pure yellow. After playing around with it and testing it on 100's of images it seems to be a reasonable compromise for most situations where Aperture 3's treatment would be not so pretty. I left this out of the standard, portrait, and neutral for reasons I will not bore you with.
If you decide that you want these presets please understand that I consider these the first beta release. I will be depending on your specific feedback with things you would like to see in future updates. Until I consider them final please keep the download link so that you can obtain free updates as I incorporate suggestions for refinements. If you do have suggestions for improvements and refinements please leave them in comments on this post. They do not have to be technical just a reasonable description of what you are seeing and what you would like to be different.