I don't really need to say more. I think the Golden Duo and the Yard folks are all pretty cool for their own reasons, as well as Irene. She's pretty badass, smart, and a good match for Sherlock. Lestrade doesn't get enough credit either. Gotta love it when he said 'not our division' with a mouth full of doughnut. xD
Moriarty, there's just something so great about villains like him. Sherlock, Irene, Lestrade, Mrs Hudson, Archie
Moriarty is my favourite and Sherlock my second. Literally every second Andrew Scott is on, he is riveting. Of course I enjoy the character of Sherlock Holmes because my personality is so like his and it is quite hilarious because I react to and do many of the same things he does in the show.
I've been a fan of the books since I was a kid because of the friendship between Sherlock and Watson and I like these shows for the same reason. It's hard not to look mediocre when you're around genius all the time; I really feel for Watson.
Watson's my favorite because he's the most relatable in my opinion. He's not as smart as all the geniuses around him; he's mostly normal and reacts to things in the way a normal person would.