[the phantom]

Hurin is either #1 or #2 on my list. My other possibility is his son Turin.
Turin lived his entire adult life under the curse of the greatest being on earth, and also got on the bad side of the father of dragons. I think it's amazing what he accomplished despite being screwed from the very start.
First, he made a name for himself on the northern marches of Doriath, being named with Beleg as the greatest of Doriath's warriors.
Then he went into the wild and took over a band of men and did more harm to Morgoth's armies, once again making his territory feared by enemies.
After that he went to Nargothrond, and even though Orodreth was "in charge" it was clear from the books that Turin was basically ordering things the way he wanted. And I believe that is extremely telling, the fact that he rose to the absolute top of a powerful elvish kingdom, where there were great elf lords in abundance. He rose above even them. And once again, he did some serious damage to Morgoth while there.
After a run in with Glaurung, during which he showed no fear, he went on to Brethil and quickly established himself as the top dog there, and once again knocked Morgoth's forces around. And this was where he accomplished perhaps his greatest feat by slaying Glaurung.
Then finally, after having his eyes opened by Mablung, he basically realized that he was a plague everywhere he went because of Morgoth's curse, so he decided he would do no further harm and take his fate into his own hands, whereupon he took his life.
Considering how tragic his life was, losing his first sister, being seperated from his father, then being seperated from his mother, being wrongfully accused in Doriath, accidentally killing his best friend Beleg, losing Finduilas, and finally marrying his sister, I think what Turin still managed to do was amazing. I would've snapped under those same circumstances. I think if he would've been given a better chance, such as being born before his lands and people in Dor-lomin fell, he would've become the greatest lord of men ever known.
I also think it's interesting that in early writings of The Last Battle (at the end of the world), Tolkien said that it would be Turin with his black sword that would deal Melkor his death blow, and called Turin the conqueror of fate, and named him among the Gods. Apparantly, Tolkien thought he was pretty special.
Forgive my long post, but I just love the tragic hero that tries his best to rise above his human flaws and less than perfect circumstances.
Like father, like son. Hurin and Turin are on top of my list.