most important element in music/prog

Melody is the essence of music.

Good post from David there.
A lot of the music in prog, well, let's face it, it's not as "out there" as some of the pure avant garde music and more extreme classical music forms.
Which means, a very large majority of prog rock is still written with a tonal center and along with that, we usually have melody.
Melody, contrary to the belief of many non musicians, is not just that kind of stuff you hear in symph prog or whatever but it can be as dissonant as hell to and melody does not have to conform to that popular belief that it has to be 'beautiful' sounding, but it's still a melody isn't it, since it's not atonal/atonality.
Yes, folks, that means all those seemingly 'noisy'  prog metal or avant bands you hear , have A LOT more melody than you realize, but it isn't always 'beautiful' and consonant, but melody is still present in many cases.

Of course, without melody, without the musical scales used to write melodies, we cannot really have harmony in the normal sense anyway, since the notes in chords that make up harmonies are derived from scales and modes in the first place, so from that, it was easy to pick melody over harmony by a long shot.
When someone writes melodies, often a rhythmic center can develop from that too.
And of course, to some extent, form and structure can rely on melodic components, but not always obviously.

Difficult poll, eh?