Pacquiao, Marquez at it again for fourth time

Manny Pacquiao, left, and Juan Manuel Marquez, right, pose for photos during a news conference, Wednesday in Las Vegas. (AP Photo/Julie Jacobson)

By now, there's nothing Manny Pacquiao and Juan Manuel Marquez don't know about each other. After 36 rounds in the ring — many of which could have been scored either way — there's not much fight fans don't know about the two, either.

What should Manny Pacquiao do next?