I like to see as much as possible of my character and its surroundings. I placed the action bars up to the left because I know from ME that it works and focus remains on the action instead of the UI. What you can't see is that my target frame is up top, vertically opposite to my own unit frame. The portrait on the right is my companions.
It's basically a mesh between Mass Effect 2/3 (haven't actually played 3) and, I guess, a bit of KotOR. Never cared for the MMO layout.