Historians who study other historians may be influenced by those they study but the essential question to me is do they in turn effectively influence historical actors?  I am willing to concede that some historians are influential in shaping events by the affect their own historical writings have on historical actors.

I think you're exactly on to it here.  Two things:First - I think that even if a historian has not really been influential in shaping history, studying about who has studied what in a field is of course good just to know what has already been written on a topic.  However, as I mentioned in a previous post, I think that this is the kind of thing that is better suited for people advanced in their fields.  Most people don't need to know all of this.  I will go ahead and agree with your basic sentiments about historiography not being "real" history, affecting "the craft of history but not the flow of history itself".  I could challenge that on technical grounds but I understand what you are saying and will leave it be for now.  I will say that just as sportswriters are likely to read articles about other great sportswriters of the past, I don't think it's surprising that historians would want to read about other great historians in history.  But again, it's something that people advanced in their fields should care more about than the average student. Second, forget about twentieth century historians for a moment.  In my field covering parts of Venetian history, I can tell you that several important histories of the city have been written - for example, in the thirteenth century, in the fifteenth century, and sixteenth century (among others).  These histories undoubtedly influenced the way Venetians saw their own city.  Because of this, these histories are vitally important to understanding how the city developed over time.  I don't think that the historians themselves are actually significant in history for things they did other than with their pens.  A history which examined how those figures influenced Venetian history would therefore be a very welcome addition to the field of Venetian history studies.I think that this fits into the part what you said, about historians influencing the course of history.  For much of history, when historians were far and few between, written histories were more important than they are today in a sense.  Those are the kinds of writings which would have been more likely to influence historical events.So in the end, modern historiography can be rather inward-looking and I can see how it can be criticized on some grounds as not being history.  On the other hand, it is useful for specialists in the field.  Further, I think that studying older, important histories through time is still very beneficial to study of history itself because they are likely to influence the course of events.I think we agree more than I initially thought. 

Here's a description of historiography which is rather straightforward, and in a nutshell:"...rather than basing itself on a systematic analysis of those textual and other remains of the past that historians traditionally call 'primary sources', historiography explores the tendencies, developments and sometimes unarticulated assumptions that inform historians' writings."Jonathan Woolfson, Palgrave Advances in Renaissance Historiography

Funny…I was anticipating you saying something else, and me agreeing that while historiography has its place, straight history is where it's at (more enjoyable, more important, more worthy of our time.  Historiography can be very helpful, but it's really only helpful if you already have a good grasp of history.

I guess something along the line of navel-gazing, and you know the rest.  I can see how it might be considered to be like that…sort of a way of stroking the ego of one's profession. 

I like to study it because I am fascinated by the evolution of ideas.  Sometimes I would rather read what historians are saying about one another than the historical subject itself.  Why that is I have no clue.