Choosing the right background and depth of field

Last week was, as usual, an exercise in refreshing my memory of photographic techniques and forcing me to follow those techniques to their ultimate conclusions. I am pleased to note that I ended up with several sequences of images that illustrate very nicely some of those processes, and as time allows, I hope to share those progressions to y'all, with pictures.

Case in point, backgrounds and depth of field. ( Pictures behind the cut to save your bandwidth )