Post Processing, Order Of Actions

So you are doing those adjustments in sequence, saving each time? Or does it just result in a different look depending on the sequence of button pushes?

I don't like to use "Auto" much, except I do like Nikon's D-Lighting function in ViewNX/2. However, it is predictable and known what it does. I have no idea what Adobe's auto functions do, though you can get used to anything once you figure it out.

One issue with "Auto" functions is they don't look at just the coin but the overall picture. Thus they try to optimize the background as well, which is not really desirable. Best thing is just to look at the histogram and optimize to improve dynamic range in the areas you care about. This usually needs to be done manually.

It looks like the Adobe sharpening routine is also much too aggressive. Does it have adjustments?

Here's your image with 10-sec of adjustment in Nikon ViewNX2:

I think the original image is fine. Once you resign yourself to doing post-processing, your expectations for the original image change. Instead of trying to make the image look "finished", you try to make it look like the best raw material possible for further adjustments. This mostly means making sure you don't either over- or under-expose any areas of the image, and that your lighting style is as you want it to look. Always remember the basic principles:
- Composition: your image is fine, maybe a little tilted CW. Better to fix this in actual coin orientation rather than rotating in post
- Focus: your image looks good, in focus just fine. I suspect this is due to a fairly small aperture since the background is also in focus
- Exposure: this is what you can work with most in post. It's always been 3rd priority because film photographers could work with this in the darkroom to get it just right as well. But with digital we have many, many more tools to work with.

Sometimes you see Focus as #1, Composition as #2, but for digital focus is often compensated for with sharpening, which was a difficult thing to do with film.