I don't often predict things this far out, but if Rick Perry enters the race, he'll win the nomination.
The Republican Party is all about three things when it comes to nominating presidential candidates. They dig contrast -- Dole, Bush and McCain were all very different than the Democrat they opposed, and Perry with his secessionist attitude and Texas hick persona is very different from President Obama. They dig repetition -- Rick Perry is very similar to George W. Bush, and the Republicans want another shot at that presidency. And they dig dress-em-up -- Rick Perry is another hack pretending to be a cowboy.
I have no idea who would be his running mate.