Without even ranking him against earlier greats, I have him behind Mayweather and Hopkins, but above Jones, Barrera, Morales, Marquez, who I think are better fighters. That Marquez proved himself better over the series, and Morales schooled him when he was in his prime has to hold him back. Of course he was almost shut out against Mayweather. Oscar was shot and drained, and starting the catchweight trend against Margarito who had been exposed as a plaster cheat shouldn't get high praise. But you can't deny the greatness of his destruction of Hatton and his dominant beating of Cotto. Those wins are what deservedly make Pacquiao a legend. Add in Clottey, Bradley, Ledwaba, Diaz, and the greats he had wins against however you want to question them, and he's one of the 50, maybe 40 greatest fighters of all time. But greater than top 20 takes ignorance of boxing history and isn't justifiable. It's just an insult to the the accomplishments of almost 20 fighters to even compare them to Pacquiao.
If you have Pacquiao top 20, can you post your all time top 30, to show what fighters you have him higher than? Do you have him higher than, say Chavez? Who many have around 20, but I don't think can possibly be ranked below Pacquiao.