If you have a Mac/PopColor

[centaur]

Here is an inexpensive app if you are using a Mac that will let you select color to enhance a subject, reverting the rest of the pic to black and white. As an example, here is the original pic;
 

Using the  POPCOLOR app available in the Mac App Store, this is a worked over pic; it is very simple and takes just seconds to do:

 

May or may not be your cup of tea, but it does add some variations to a regular photo.