Is Chopin's Prelude in E minor, Op. 28 more consonance or dissonance?
 

I find it closer to consonance, but a couple of my buddies are arguing that its more dissonance. What is your opinion?

Western tonal music uses alternating dissonance and consonance to create forward motion. There are certain chords in the Chopin prelude that are dissonant, but they are counterbalanced with consonant chords. This is a pretty standard sort of situation. They are probably saying that it's dissonant because the piece is in a minor key. Our culture informs us that this is the "sad" mode, so they're hearing that and ascribing the emotional effect to dissonance instead.

It is consonance indeed.