Thanks for joining the Creative Effects team fotofrank , and for the great challenge you gave us!
There has been some interesting discussion and images recently about black & white photography and the value of removing the distraction that color sometimes causes. That reminded me of a technique that I especially like: keeping only the subject in color and de-emphasizing the rest by rendering it in black & white.
Here is one tutorial on changing an image to B&W with a Touch of Color. There are some obvious improvements that can be made, but this one has the advantage of being particularly easy; just 2 steps! Here is my example of this technique:
We are off to a very good start! Thank you for trying it out and sharing your results.
I like how bobharron use of a blur further isolates the subject from its surround but still gives context and texture. The iamge Major Major made reminds me of an Out Of Bounds treatment, but much easier to do and gives a unique effect.