Just read an identical thread. Sorry about the blunder? In that thread, someone posted that Nakamura does not qualify for the next Candidate's match. How can that be true? Nakamura is ranked no.4 in the world.
If Carlsen wins, ...

http://en.wikipedia.org/wiki/World_Chess_Championship_2014
I'd like to see a match between Carlsen and Ivanchuk. That won't be happening either though.
...who would you like to see play against him in the next world championship?
I choose Hikaru Nakamura! Currently ranked no.4 in the world. His style is self-described as attacking, like his hero Kasparov. So, it would be like Karpov (Carlsen/positional) vs. Kasparov (Nakamura/attacking).