Which show should I watch first?

I'm torn about what show to watch: Merlin, Firefly, or Bones. Now Bones I watch all the time but I'm behind on the last 4-5 episodes this season and I need to catch up. I watched Serenity which is the movies created after the t.v. show Firefly and it was good. I've watched bits and pieces of Merlin at my parents' house but never actually watched an episode. Now all these shows I can watch on Netflix but I'm having hard time deciding. What do you think?