That's an awesome list. I can't vote. There isn't a nickel's worth of difference between some of those guys. If you made your criteria more specific, it might be easier to pick one.
Pfft....... That's just a who's who of the best fighters of that period, other than the heavies. I can't really vote for Roy Jones...... I know he won a version of the HW crown, but it was against the weakest champion, if he had beaten Byrd then perhaps.... also he never defeated a linear champion in his entire career - DM counts against him IMO. Hearns I like a lot, faced probably the best LHW around at the time in Virgil Hill, and although the fight was pretty close, it was an excellent boxing display. If DLH had received a bit more luck from the judges he would be in with a shout - the only decision fight he definitely lost was the Mayweather one. Each of the others you could argue in his favour - he certainly beat Trinidad and Mosley in the rematch.
he did actually recieved a lot of luck from the judges.. quartey-sturm and whitaker victories can be considered as lucky
i voted for the pac-man....not only has he moved up in weight and fought world class opponents(discounting oscar and maybe ricky) he has moved up with power and looks like a machine...
DLH. Fought the best of his era in every weight class and you can honestly only say he lost 2 fights. Hopkins and Pacquiao. The rest could have gone either way and were usually against top elite fighters in their prime.