Mauer is first, no doubt. Its going to be interesting to see if the big guy can make a career of it behind the plate.
Molina is second on defense alone. He is, flat out, the best defensive catcher in baseball. He is like Ivan in his prime.
Honestly, no one else is even close to either one of these guys. Now, in five years, when Bryce Harper is leading my Nationals to the pennant, then we'll talk