I hope you're saying he's brave only because he's fighting Margarito?? But yeah, he is a brave dude as well as a lot of other fighters..
you can make a case for a lot of fighters for being 'the bravest'... For me, look at vargas... he fought winky, ike, thompson and trinidad in the span of 1 year!!!! in his early twenties and with less then 20 some odd fights... Mosley as of right now is showing his grit and courage... no doubt... when oscar is fighting mayweather and pac he is fighting cotto and margarito... I think you get to a stage though where its hard to seperate them... they all have balls of steel at some point.
Mosley is the exemplification of a champion. He has taken on fighters no one else wanted to get near - such as Forrest and Winky Wright. Now at this advanced stage of his career - he is going after Margarito.
I'll accept an argument for DLH, but just to play devil's advocate, two points: 1. DLH always had some angle when choosing his opponents. 2. Ironic, isn't it, that the fighter slated to face Pacquiao at 147 is getting credit for being braver than the one about to sign a fight with Margarito.
Those are fair names to mention, both of which certainly belong in the conversation. On resume (as someone noted) Hopkins has fought nothing but elites his last six fights, and considering his age, that's an absolute marvel! A modern day Archie Moore if ever there was one! As for Pacquiao, who can question his bravery in the ring? Certainly not me. But I put Shane in the same light. It's not over all resume, and it's not even quality wins. But Shane fought a bunch of tough fighters, that he could easily have avoided (Forrest & Wright), and after losing to each, he demanded they do battle again in an immediate rematch. Fought Cotto when few wanted to take that risk, and now it looks like he might fight Margo? All I have to say is Shane has ALWAYS dared to be great and sought the best. Same with Pacquiao, and for the most part, Hopkins. Can the same be said of Mayweather? :smoke