You may know that one of the topics of interest to me is the origin of names - and all sorts of other topics to do with names and naming. I even devote an entire blog on the subject, which is, of course, called By Any Other Name.
The links between family names and geography is quite a fascinating one, especially if the names in question happen to be part of your own family history.
Here are a few links to websites you may find interesting:
Public Profiler - World Names
(I have used it mainly to find out the common surnames of particular districts, especially in Italy and Belgium.)
Public Profiler - GB Names
(I have used the surnames page with the year 1881 chosen, and have discovered more about my family origins that way.)
Guild of One-Name Studies
Wikipedia - One-name studies
Wikipedia - Surname DNA project
Many of my own ancestors' family names are very common, though with many variations in their location. Having regional family origins may sometimes become clearer through a one-name search, though it still depends on tracing back the written records step by step.
Here are links to a couple of my By Any Other Name blog posts about family names. I hope they will enhance your reflections:
Family honour and freedom
Origins of family names
And here are a few Wikipedia links to some of the very common surnames that have appeared in my family history - though none of my relatives have biographies on Wikipedia, as far as I am aware:
Bailey | Barker | Cole | Harris | Lloyd | Clark or Clarke | Rowe | Morgan | Nash | Howell or Howells | Wilson | but I am yet to find a Smith or a Jones!
What are the most common surnames in your family history - and the most unusual?