(This seems like a good place for my first post, albeit a bit late to the party).
1. Sherlock
His absolute drive, and his complete loyalty to John/he lies to himself too much
2. John
His quick temper, his willingness to rein Sherlock in/his tolerance
3. Mrs. Hudson
Her kindness/her tone of voice, sometimes
4. Molly
Her willingness to help her friends/how easily persuaded she lets herself be
5. Lestrade
His smile, ability to ask for help/.... Nothing, he's pretty awesome.
6. Mary
She sees right through Sherlock/didn't trust her husband enough with her story
7. Mycroft
He's pompous, obnoxious, a bit of an automaton, my favourite character. I love the sibling rivalry and his protection of Sherlock.