[Keneldil the Polka-dot]

I'd say Beren. He faced Morgoth, stole a Silmaril (with help), and married Luthien. If you've seen burrahobbit's graph, Luthien maxed the scale in the "hotness" index, so that carries weight for Beren. He navigated through Dungortheb where all Ungoliant's spawn lived, and came to Doriath "by paths that no Man nor Elf else ever dared to tread" and the Girdle of Melian could not stop him. He went to the Halls of Mandos and came back. Here on earth we have only one guy who came back from the dead. Beren has a pretty impressive resume.