I know, I'm spectacularly late to the party on this one, but I recently reread Stephen Volk's essay, Naming Names, and got to thinking...
The subtle (and fun) effect that a well-chosen character name can have on a reader, whether they notice it or not, is, I'm sure, too often overlooked. I remember reading of a study, as reported in Men's Health (I think), that male names that begin with sounds that are produced at the "front" of the mouth are viewed as more attractive than those that begin with sounds produced at the "back" of the mouth. For instance, names that begin with the 'B' or 'D' sound are more attractive than those that begin with an 'H' or 'R' sound (or 'A' sound, for that matter--my name's Andre, by the way).
Similarly, the names of many Golden Age comic book characters were aliterative because writers and editors believed such names were easier to remember and generally more pleasant. Hence, Peter Parker, Bruce Banner, Lana Lang, Lois Lane, and, of course, Clark Kent. These names, though, their poetry aside, are quite plain.
To add to or expand upon points Mr Volk made regarding the choice of a 'plain' character name, namely (no pun intended) King's Johnny Smith, such an everyman (or everywoman) name can denote and help define an everyman character. But beyond signalling down-to-Earth-iness, a more common name might also help the reader identify with the character in question.
Sherlock Holmes has a strange, compelling name, but he is also a strange and compelling character. However, the reader experiences Holmes' adventures through the eyes of Dr John Watson, the detective's sidekick and the story's narrator. Watson is a more 'average' individual, one with which the reader can identify, one with which the reader will share his awe of Holmes' deductive prowess, and, as such, Watson has a more common name, one that inspires not wonder or curiosity, but familiarity.
The same is seen in more modern writing. The reader does not follow Dumbledore or Hagrid, or even Hermione, through the halls of Hogwarts, but the humbly named Harry Potter. Aloysius Pendergast of the thriller series penned by Lincoln Child and Douglas Preston is the star of those books, but, though they are written in the third person, the mysteries are experienced primarily by and through Sergeant Vincent D'Agosta. A straight man, with a suitably straight name, is needed to give the reader an in, a point of view closer to their own real life one.
Of course, in the case of those above-named super heroes, the reader is permitted to identify with the mild-mannered and plainly-named secret identity (especially in the case of Peter Parker and Clark Kent), while the heroic alter-ego provides the wonder and awe.
Just some thoughts generated by an interesting article.
Big thanks to Mr Volk.