The Music of the Ainur cannot be compared to the other deeds of Eldar and Men because no matter what the Children do, how can anything of theirs surpass the greatness of a whole world being called to life?
The Music didn't call a world to life, it merely generated a vision of what should be
, not what is. The Valar still had to achieve it after grunting it before Eru. That's why I don't think much of it.
I voted for Fingolfin's duel, merely because I couldn't vote for the other choices : Frodo did not destroy the Ring, for he failed in the end, and it was luck/fate that did it; Fëanor's speech was merely the wallowing of a raving madman, à la Goebbels; killing the Witchking was pathetic, just putting a sword under a crown after Merry had done all the work; Túrin just sneaked under Glaurung to kill the beast : very heroic; and there's nothing special about Gandalf's resurrection : a naked guy on top of a snowy mountain. Sheesh.
Of course, Fingolfin's duel was quite ridiculous too; you might as well try to kill a blue whale with a needle, but at least the lad did it with bravura.
No, Beren & Lúthien entering Angband should've been included in the poll.
Give up the Halfring, she-elf...