Jones would probably be first. Mayweather would be a close second, though. They're the two best boxers since SRL.
Mayweather Jones Jr wouldn't even be the #1 super-middleweight or lightheavyweight. In supermiddleweight Froch, Ward and Kessler would all beat him. Light-heavyweight, Stevenson, Kovalev and possibly Hopkins would beat him. Not that Roid Jones would fight Froch, Kessler and Kov anyway... he seemed to have a phobia of fighting European fighters and so DUCKED them.
Probably Mayweather after his fight then Rjj after he fights and so on kind of how Pac and Floyd were
http://www.youtube.com/watch?v=G0Erh4RKbHE IF Roy was in his prime today this is what we would see... Fighting cabdrivers and making excuses, you know the usual when it came to Roy.
Floyd was always behind Jones when he was relevant in the P4P rankings and that would be no different today. People always like to say that the current no 1 is best of this and that "generation" but the fact is that there is not a huge age difference here and they were both multi weight world champs at the same time and Jones was miles ahead.