  I recently read my first Sherlock Holmes stories and so I can finally understand what all the fuss is all about. Like why his silhouette is all over Baker St station in London and why he's so famous that people think he was real and Watson really was his biographer.
The technique of using Watson as Doyle does is very effective. It means we are able to get close to the character without losing the mystique of when a complex person explains themselves directly to us. In fact, we are probably able to get a better view than if that had been the case because it's undoubtedly true that people often see in us what we don't see for ourselves, good and bad.
As one critic said, it is not the stories themselves which keep people coming back for more because, although clever, they are utterly formulaic and even predictable. Rather, it is Holmes himself that people love, myself included. He is egotistical and egocentric but more quietly smug than overtly arrogant. Best of all, he has terrible moods, uses cocaine, drinks, smokes and adores music. What more could you want of a classic hero? 
