This is my current default, until I get bored or find another shot I want to use for a while.
Usually saved for comments or posts that are a bit fun or silly, where one of my other icons don't quite work.
I use this one for posts where my thoughts are running deeper and more seriously than the norm.
Used for posts and comments that... hard to find the words for... give me an internal lift, that touch me in deeper ways than normal, or when I want to get across that undefined magic or feeling. Posts of subtle but deeper feeling, usually joy or pleasant melancholy.
Used for travel posts.
Used for those posts where my opinion is obviously the most important! :P
Used for certain type of geeky, dalek-y, Doctor Who-y, silly posts. I love this icon!