Here's a fun site to discover new authors, and new books to love -- the Literature Map. Now, I'm not positive that I agree with its results. For example, I don't know that the closest author to Alexander McCall Smith in my mind is Jan Karon (not that I don't enjoy her work, as well), but hey.
The map explains that the closer two names appear on the map, then the higher the likelihood that the reader will enjoy the works of both authors.
It's a very fun site, and after scanning thru Alexander McCall Smith, I'm reminded that I've been wanting to read Christopher Buckley -- so I've put his name on my list for this week.
They may have something here! Check it out -- it's a fun site.