I had a thread a while back in which I pitted Duran vs Whitaker @ lightweight and got a lot of good responses. I think Whitaker was best @ 135 and pretty close to unbeatable at that weight. I agree with the previous posts that said Duran would have a good chance but outside of him I don't think there was anyone who could whip SweetPea at lightweight. That being said I believe he could be defeated at 140 and 147 by some of the greats. Whitaker's reflexes and defense just wouldn't allow for him to be soundly beaten at those weights but it could be done because Whitaker was not a huge guy......even at lightweight. I would give Mayweather, Pacquiao, SRL, Hearns(how will Whitaker combat the reach) a chance at jr welter and welter but his style just makes it difficult to say that anyone would DEFINITELY beat him in his prime. Just too cagey and awkward.