As you can see, Chris Christie leads the poll with 18% -- but that far from a number that would make him a real favorite. With no candidate getting even a fifth of the vote, the only real thing that can be said is that there is no favorite yet. This is still a wide open race that anyone (even a currently unknown candidate) could win.
It does look like Paul Ryan has taken a hit among Republicans because of his reaching a budget agreement with Democratic Senator Patty Murray. At the end of October, Ryan was the choice of about 22% of Republicans. He now is the choice of only about 10%.