Pretty hard to make a list like this, there is too much subjectivity but...

I woiuld say that George Foreman is far too high.

I can't see Duran at #6, sure he has a tough guy image but his record doesn't justify #6, not enough big name scalps. Top 20 maybe, but not #6

Arguello is far too low. I can't see how Arguello should be that much lower than Duran, if at all.