Armando, thank you for the detailed share of your experience.
If some of the Nik plugins help you process your images (many of which I have admired), I surely would see their usefulness.
I know that the examples shown on the software's websites are a bit exaggerated to make their effect clear, but they look quite unnatural.
I feel the need of the noise reduction less and less thanks to the fact that the noise, especially the chrominance noise, from the current sensors looks less bothersome.
Personally I rarely apply sharpening to my images. I prefer the rounder rendition even for the focused point, and the image will look sharper anyway when reduced in size for posting on the web. The contrast and clarity sliders do the trick well enough for me.