[Pitchwife]

No question - Thingol. He's by far the strongest character, even Celeborn and Círdan pale by comparison. What we see of Thranduil in The Hobbit is more or less a replica of Thingol in the Silmarillion (cf their underground dwellings in the middle of a great forest, their haughty dealing with the dwarves); Amroth has an interesting story, but we don't hear much about him as a ruler (same with Legolas), and Oropher and Amdir are mere historical footnotes.

Also because while he acts like an arrogant, overprotective jerk in the story of Beren and Lúthien, he shows his ability to learn from mistakes by becoming a loving foster-father to Túrin.