Study Time

Personally, I like Sherlock as a Slytherin and John as a Gryffindor best. I can kind of see Sherlock as a Ravenclaw but I can't see John as a Hufflepuff, sure he's very loyal but so are like 99% of the Gryffindors (basically everyone excluding Wormtail, Harry, Ron and Hermione were about as loyal of friends as possible.) John was an army doctor and John Watson is not only known for his loyalty but also his bravery as well. Sherlock (at least the BBC version) is cunning and sneaky, another point is that Slytherins are often judged as being evil or dangerous even though that not necessarily the case and this is how Sherlock is seen as well; most people in the series judge him as being evil, dangerous and/or heartless and either hate or are afraid of him. John's the only one who really sees past that. Plus, I'm kind of a sucker for the whole forbidden/unlikely friendship concept between a Slytherin and a Gryffindor (which is basically what Sherlock and John's relationship is already like.)