I Don't Do Serial Killers!

I am probably the last person in the universe to read The Girl with the Dragon Tatoo. Spoiler alert--if there is another person after me who has not read it, please disregard this post. I shall give away plot points.
For the first two hundred pages I was
a. enjoying it as an interesting read but
at the same time wondering why it generated so much buzz as it was not particularly exciting or unique.

Then I got to the nitty gritty and found that the family secrets included a branch of sadistic serial murderers. And that was it for me. I don't do serial killers. I find them a real cop-out for the mystery writer. I would much rather read about an ordinary, normal person who has been driven to kill by circumstances that might put any of us in his position. I like to see all my characters as humans to whom I can relate. 

The twisted warped mind of a serial killer may be fascinating as a psychological study, but it doesn't play fair with the readers on the whodunit level. Obviously a good serial killer leaves no motive clues, because the only motive is his crazy gratification.

So I had hoped that the skeletons within the Varner family in TGWTDT would have been those of greed, betrayal, fear... those motives with which we can identify.

So please share your opinions. Do you enjoy serial killer stories? Do you think that writers write about them because they are shocking and scary and thus have 'bestseller' potential?  Did you like the GWTDT?  Do you think it deserved the hype?