My opinions:
I also think it's Eleven, but Hopper will become the new main antagonist of the second season after he kidnaps her, or he could be protecting her from something, so there is a possibility for a new antagonist.
Eleven. She's an outcast and I love that. I see a little of me in her, so she's my favorite.
I also love Joyce because she's so determinant and never gives up. (I know that sounds cheesy).
Barb was actually really nice because she waited for Nancy but Nancy chose to leave her to die. :/