I like to change the photograph regularly; it's a thing I do, usually around the first of the month. I set it not only on this site, but as my Facebook cover photo, my desktop wallpaper, my phone lockscreen, and even on my Nook. Below is a brief description of why I'm using the photo I'm using.
I love this photo for its beautiful contrast and imagery. Unfortunately, it's difficult to position it properly with my existing CMS, so you don't get to see it all. Fortunately, here you can see it in all its glory.