Friend or Follow

I am looking at who I follow/am followed by on Twitter, and was looking for a tool which would give me an idea. As a first run, I have found http://friendorfollow.com very helpful in identifying those who I am following but are not following me. Some people will only follow those who are following them, which isn't my style (as some of the biggest names, who post the most interesting tweets (e.g. @mashable) don't follow many…