I chose the name that my mom so luckily revealed to me had I been born genetically female. My chosen middle name is the same.
When I joined this forum I originally went by Victoria/Tori. I have to say that choice fits into the last category of the poll. Although it wasn't so much that I admired the individual (I did), I just really liked the name. I thought it was beautiful, and I was going through a phase... I was a teenager... where for whatever reason I wanted to go by something else other than Emily.
However, in the last five years it has been Emily/Emma for me. Emma is a name I chose to go by with my first friend that I came out to because she had another very close friend that was named Emily. Say that's an incredibly poor reason for me to have to change my name or not, but it caught on and for everybody else I came out to I just decided to go with it. Although they all know that Emily is my real chosen name.
Probably doesn't need to be said, but initials never had anything to do with it. I could come up with many combinations to keep to the same initials, but I just don't care. I think it's more 'respectful' to go by the names I would have been given.