Always Read the Book
So far I have read A Study in Scarlet and The Sign of Four. They are delightful, and the portrayals of Holmes as an absolute jerk are unfounded. (I really despise Cumberbatch's portrayal, but I don't think he's really supposed to be Holmes.) He's aloof, unemotional, sometimes arrogant (but capable of admitting mistakes), and sometimes kind and giving; yes, he does take cocaine at times (which was not a huge deal back then), but not every day.
Always read the original source material. Movies can be very nice versions of the originals, but usually they get it wrong somehow simply because they are not the same medium. It's like the difference between a photograph and a painting. One is more directly the work and intent of the artist and his/her talent; the other has to be mediated through a machine.
(January 17--I have read 27% of The Adventures of Sherlock Holmes and I'm still looking for Benedict Cumberbatch.