I've got a few, and I'm sure there will be a groan when I say this .... but Firefly is by far one of my favorites. Other notables are Doctor Who, Supernatural, The Unbreakable Kimmy Schmidt, and Buffy/Angel.
There wasn't enough of Firefly for it to be my favourite. It's maybe like a sixth of a series. It'd be like picking a favourite movie when all I've seen of it was a super amazing trailer.
Ramen, brothers and sister. Ramen.